APPROVED CODE OF PRACTICE FOR THEPPRORACTICE
SAFE USE OFISOCYANATES
Published by the Occupational Safety and Health ServiceDepartment of LabourWellingtonNew ZealandMarch 1994ISBN 0-477-03454-3$10 (incl. GST)
P501/080/4000/1994
CONTENTS
NOTICE OF ISSUEFOREWORD
SUMMARY OF THE HEALTH AND SAFETY IN EMPLOYMENT ACT 1992
APPROVED CODES OF PRACTICEEMPLOYERS
HAZARD MANAGEMENTINFORMATION FOR EMPLOYEESEMPLOYEES
1. INTRODUCTION2. INTERPRETATION
2.1ISOCYANATE CLASSIFICATION2.2
SCALE OF USAGE
3. DEFINITIONS4. RELATED LEGISLATION5. CHEMICAL DATA
5.1PROPERTIES5.2
REACTIVITY
6. HAZARDS AND HAZARD CLASSIFICATION
6.1GENERAL
6.2BREATHING OF VAPOUR, AEROSOLS AND DUSTS6.3EFFECT ON EYES6.4EFFECT ON SKIN
6.5HAZARDS FROM UNDESIRABLE REACTIONS
6.6
HAZARD CLASSIFICATION AND SCALE OF OPERATION
7. PLANT DESIGN
7.1GENERAL
7.2VENTILATION
7.3DRUM HANDLING AND STORAGE7.4DRUM EMPTYING
7.5BULK STORAGE, TANKS AND LINES
7.6PUMPS AND FILTERS FOR TDI CLASS MATERIALS7.7
MOULDS
678
889910
1112
1212
131415
1515
17
171718181819
20
20202323242525
7.8STORAGE OF FOAMED MATERIAL7.9
DUST FROM CURED FOAM
8. PLANT OPERATION, TRAINING AND SAFETY
8.1EMPLOYEE EDUCATION, TRAINING ANDRESPONSIBILITY
8.2INFORMATION AND WARNING8.3SPILLAGES8.4WASTE DISPOSAL8.5EYE-WASH FACILITIES
8.6RESPIRATORY PROTECTION
8.7PROTECTIVE EQUIPMENT AND CLOTHING
8.8
CLEANING AND REPAIR OF TANKS AND ASSOCIATEDEQUIPMENT USED FOR THE MIXING AND STORAGE OFISOCYANATES9. MEDICAL REQUIREMENTS
9.1EMPLOYEE MEDICAL SURVEILLANCE9.2FIRST AID
9.3ATMOSPHERIC TESTING FOR ISOCYANATES9.4CONTAMINATED DISCHARGES9.5
LABELLING
10. APPLICATION OF POLYURETHANE PAINTS AND LACQUERS
10.1GENERAL
10.2URETHANE OILS AND ALKYDS
10.3BLOCKED ISOCYANATE COATINGS
10.4POLYISOCYANATES: APPLICATION BY SPRAY,
BRUSH OR ROLLER10.5SPRAYING OPERATIONS OUTSIDE OF SPRAY BOOTH10.6CONSTRUCTION MATERIALS FOR SPRAY BOOTHS
AND DRYING OVENS
10.7ISOCYANATE OVER-EXPOSURE10.8EMPLOYEE TRAINING
10.9REMOVAL OF POLYURETHANE PAINT10.10 EMPLOYEE MEDICAL SURVEILLANCE10.11 ISOCYANATE MONITORING10.12 LABELLING
APPENDIX 1: WORKPLACE EXPOSURE STANDARDSAPPENDIX 2: SPILLAGE PROCEDUREAPPENDIX 3: DECONTAMINATION MIXTURES
APPENDIX 4: SAMPLE HANDOUT SUITABLE FOR TRANSLATIONAPPENDIX 5: SPECIMEN WORK PERMIT
4 SAFE USE OF ISOCYANATES
2526
27
27282828292930
30
32
3233343535
36
363636363940404141424343
4445464748
APPENDIX 6: REQUIREMENTS FOR AIR QUALITY (COMPRESSORS OR CYLINDERS)FOR SUPPLIED AIRLINE RESPIRATORS49
1. AIR SUPPLY
2. COMPRESSED OXYGEN SUPPLY
4951
APPENDIX 7: MEASUREMENT OF AIR MOVEMENT IN FULL DOWN-DRAUGHTBOOTHS
APPENDIX 8: GUIDANCE NOTE ON RECOMMENDED CONSTRUCTIONMATERIALS FOR SPRAY BOOTHSAPPENDIX 9: RELATED LEGISLATION
525354
SAFE USE OF ISOCYANATES 5
NOTICE OF ISSUE
6 SAFE USE OF ISOCYANATES
I have issued this Approved Code of Practice for the Safe Use of
Isocyanates, being a statement of preferred work practices or arrangements,for the purpose of ensuring the health and safety of persons to which this codeapplies and persons who may be affected by the activities covered by the code.
C J McKenzieSecretary of LabourJune 1993
FOREWORD
I have approved this statement of preferred work practices, which is an
Approved Code of Practice for Safe Use of Isocyanates under Section 20 ofthe Health and Safety in Employment Act 1992. When a code is approved, aCourt may have regard to it in relation to compliance with the relevant sectionsof the Health and Safety in Employment Act. This means that if an employer inan industry or using a process to which an approved code applies can showcompliance with that code in all matters it covers, a Court may consider this tobe compliance with the provisions of the Act to which the code relates.
Hon Maurice McTigueMinister of LabourJune 1993
SAFE USE OF ISOCYANATES 7
SUMMARY OF THE HEALTHAND SAFETY IN EMPLOYMENTACT 1992
The principal object of the Health and Safety in Employment Act 1992 is toprevent harm to employees at work. To do this it imposes duties on, andpromotes excellent health and safety management by, employers. It also
provides for regulations and codes of practice that set more detailed minimumstandards.
The following information is a brief outline of provisions of the HSE Act.Copies of the Act and associated regulations may be purchased from any GPBooks shop or any Occupational Safety and Health Service branch offices.
APPROVED CODES OF PRACTICE
The Act allows for the development and approval of statement of preferredwork practice, known as “approved codes of practice”. These are
recommended means of compliance with provisions of the Act, and may includeprocedures which could be taken into account when deciding on the practicablesteps to be taken. Compliance with codes of practice will not be mandatory.However, they may be used as evidence of good practice in Court.
EMPLOYERS
Employers have the most duties to perform to ensure the safety and health ofemployees.
If you are an employer then you have a general duty to take all practicablesteps to ensure the safety of employees while at work. (This is set out insection 6.) In particular, you are required to take all practicable steps to:
•Provide and maintain a safe working environment;
•Provide and maintain facilities for the safety and health of employees atwork;•Ensure that machinery and equipment in the place of work is designed,made, set up, and maintained to be safe for employees:•Ensure that employees are not exposed to hazards in the course of theirwork; and•Develop procedures for dealing with emergencies that may arise whileemployees are at work.
8 SAFE USE OF ISOCYANATES
HAZARD MANAGEMENT
Employers must identify hazards in the place of work (previously existing, newand potential) and regularly review these to see whether these hazards aresignificant and require further action. Where an accident, serious harm or anevent, which in different circumstances might have caused harm to any personoccurs, an employer must record it in a register of a prescribed form. Theemployer must also investigate whether it was caused by a significant hazard.“Significant hazard” means a hazard that is an actual or potential cause orsource of—
(a)Serious harm; or
(b)Harm (being more than trivial) the severity of whose effects on any
person depend (entirely or among other things) on the extent orfrequency of the person’s exposure to the hazard; or(c)Harm that does not usually occur, or usually is not easily detectable, until
a significant time after exposure to the hazard.Where the hazard is significant, the Act sets out the steps an employer musttake.
•Where practicable, the hazard must be eliminated;
•If elimination is not practicable, the hazard must be isolated;
•If it is impracticable to eliminate or isolate the hazard completely, then the
employer must minimise the hazard to employees. In addition, theemployer must, where appropriate:
−Ensure that protective clothing and equipment is provided, accessible
and used;
−Monitor employees’ exposure to the hazard;
−Seek the consent of employees to monitor their health; and−With informed consent, monitor employees’ health.
Employers must establish systems for this process of identifying and managinghazards. In situations where exposure to the hazard can only be minimised, theemployer must ensure the systems put in place to protect the employee areused. Employers need to involve employees in the development of systems andemergency procedures to be used (section 14).
INFORMATION FOR EMPLOYEES
Before an employee begins work their employer must inform them of:
•Emergency procedures;
•Hazards the employee may be exposed to while at work;
•Hazards the employee may create while at work which could harm other
people;
•How to minimise the likelihood of these hazards becoming a source of
harm to others; and
•The location of safety equipment.
SAFE USE OF ISOCYANATES 9
SAFE USE OF ISOCYANATES
The employer is also required to inform employees of:
•The results of any health and safety monitoring. In doing so, the privacy
of individual employees must be protected.
The employer must ensure employees are either sufficiently experienced to dotheir work safely or supervised by an experienced person. In addition, theemployee must be adequately trained in the safe use of equipment in the placeof work, including protective clothing and equipment (section 13).
An employer is also responsible for the health and safety of people who are notemployees. An employer must take all practicable steps to ensure that an
employee does not harm any other person while at work, including members ofthe public and other visitors (section 15).
Effective safety management should involve everyone in a place of work.Employers have specific responsibilities but employees should look afterthemselves. If you are an employee, then the Act gives you responsibility foryour own safety and health while at work. You must also ensure that youractions do not harm anyone else.
EMPLOYEES
101. INTRODUCTION
The aim of this code of practice is to provide for the safety and protection ofhealth of all personnel involved in industrial processes which use isocyanates.Its purpose is to give enough information so that a well-operated plant will
follow from the observation of the code. The intention is to display the approachneeded to all aspects of design and operation of the plant to make the use ofisocyanates a safe procedure.
Isocyanates are chemicals used in the production of polyurethane materials. InNew Zealand the manufacture of flexible and rigid polyurethane foam accountsfor the bulk of isocyanate usage, with polyurethane paints and lacquers alsohaving considerable importance. Further products using isocyanates areurethane rubbers, adhesives and binders.
Sections 2 to 6 are general provisions applicable to all isocyanate users.
Sections 7 to 9, while aimed primarily at the foaming industry, should, with thenecessary modification, be used by other industries using isocyanates such aspaint manufacturers and the printing industry.
SAFE USE OF ISOCYANATES 11
2. INTERPRETATION
2.1ISOCYANATE CLASSIFICATION
Because of significant differences in volatility between the various commonisocyanates, it is convenient to divide them into two classes based on these
volatilities. TDI class isocyanates have significantly greater volatilities at a giventemperature than do MDI class isocyanates. The division into classes and itsimplications for precautions relating to health and safety are discussed in section6.6 of the code.
2.2SCALE OF USAGE
Three different categories based on the scale of operation, i.e. low user,medium user and high user are defined in this code (see section 6.6.6).
12 SAFE USE OF ISOCYANATES
3. DEFINITIONS
Act: Means the Health and Safety in Employment Act 1992.
Employer: In this code the term employer is taken to include principals,
contractors, subcontractor, or person who controls a place of work as definedby the Act.
Inspector: Unless specified, means an inspector appointed under the Act.MSDS: Material Safety Data Sheet.
OSH: Occupational Safety and Health Service of the Department of Labour.Standard: Means the current standard published by Standards New Zealand oran equivalent overseas organisation. A list of the relevant standards current atthe time of publication is appendixed, however, as they are regularly updatedtheir current status should be checked.
Regulation: Unless specifically defined, means a regulation made pursuant tothe Act or a regulation made pursuant to the Factories and CommercialPremises Act 1981, that has not been repealed by the Act.
WES: Workplace Exposure Standards are guidelines for assessing the
adequacy of the measures taken to limit exposure to airborne substances in theworkplace. The WES booklet is updated and published regularly by OSH. It isobtainable from OSH branch offices.
BEI: Biological Exposure Indices as described in the WES booklet.TWA: Time Weighted Average as described in the WES booklet.STEL: Short-Term Exposure Level as described in the WES booklet.
SAFE USE OF ISOCYANATES 13
4. RELATED LEGISLATION
While this code specifically deals with isocyanates there is other legislation withmore general application which also should be considered. A list of thislegislation current at the date of publication is given in appendix 9.
14 SAFE USE OF ISOCYANATES
5. CHEMICAL DATA
5.1PROPERTIES
Organic isocyanates are chemicals characterised by the general chemicalformula R(NCO)x. The two most commercially important isocyanates aretoluene diisocyanate (TDI) which is also known by the synonyms tolylenediisocyanate or toluylene diisocyanate, and 4,41 diphenylmethane diisocyanate(MDI) which has the synonym methylene bis (4-phenylisocyanate). Theabbreviations TDI and MDI are now universally used and understood in theindustry.
The table on the following page summarises the principal properties of
commercially available TDI and MDI in the form of pure products or mixturesof isomers and oligomers that constitute the bulk of the market. Properties ofsolvent-based systems and prepolymers are not given because of their widevariation in composition.
5.2REACTIVITY
Both TDI and MDI are denser than water and will sink to the bottom of water-filled containers. Although they react with water, the rate of reaction is veryslow at temperatures below 50°C. At higher temperatures the reaction of TDIand MDI with water liberates carbon dioxide gas and a solid, insoluble mass ofpolyureas is formed.
TDI and MDI will also react with basic materials such as sodium hydroxide(‘caustic soda’), ammonia, primary and secondary amines and with acids andalcohols. The reaction may be violent, generating heat which can result in anincreased evolution of isocyanate vapour and formation of carbon dioxideleading to a build-up of pressure within closed containers.
The high reactivity of isocyanates is the basis for the poly-addition process forpreparation of polyurethane plastics and foams.
Neither TDI nor MDI is generally corrosive towards metals (except aluminium)at ambient temperatures.
SAFE USE OF ISOCYANATES 15
Principal Properties of Commercially Available TDI and MDIPhysical state atnormal temperaturesColour
OdourSpecific gravity(at 25°C)Boiling Point (°C)
Flash Point (°C)Fire Point (°C)Freezing Point (°C)Vapour Density(air = 1)Vapour pressure(mbar at 25°)WES** (ppm) (mg/m3)*pure MDI = 38°C** See Appendix 1
16 SAFE USE OF ISOCYANATES
TDI
Liquid (thin)
Colourless to paleyellow (clear)
Pungent (characteristic)1.22
250
127145Below 146.0
3 x 10-20.020.14MDILiquid (oily)
Dark brown (opaque)
Earthy, musty (characteristic)1.23
Polymerises about 260°C withevolution of carbon dioxideOver 200Over 200Below 10*8.5
Below 10-4
0.020.2
6. HAZARDS AND HAZARD
CLASSIFICATION
6.1GENERAL
6.1.1
All isocyanates are potentially hazardous materials and require care inhandling. From the practical point of view the principal hazard arises fromthe vapour (rather than the liquid) and hence the degree of hazard dependson the vapour pressure of the particular isocyanate concerned.
In the case of TDI the vapour pressure is such that at normal temperaturesthe concentration of vapour in air will exceed the WES. Hence, full
precautions are necessary whenever TDI or TDI-containing products arehandled.
By contrast, MDI has a lower vapour pressure at atmospheric temperatureand with adequate ventilation a vapour concentration approaching the WESis not reached. However, two exceptions are (a) spray applications whereairborne droplets (aerosols) present a hazard at normal temperatures; and(b) the dust arising from the handling of pure MDI (solid at normaltemperatures). Full precautions must be taken in both these instances.It should be noted that detection of isocyanates by smell is dangerous as theodour threshold is above the WES although the actual odour threshold willvary from individual to individual.
6.1.2
6.1.3
6.1.4
6.2BREATHING OF VAPOUR, AEROSOLS AND DUSTS
6.2.1
Vapours, aerosols and dusts of isocyanates will irritate the membranes of thenose, throat, lungs and eyes. Exposure will produce a variety of symptomswhich may include watering of the eyes, dryness of the throat, tightness ofthe chest (and sometimes difficulty with breathing) and headaches. Theonset of the symptoms may be delayed until several hours after exposurehas taken place.
After prolonged exposure some individuals may become sensitised. Thesensitivity reaction takes the form of an asthmatic attack which may occurimmediately or some time after exposure. Individuals may also becomesensitised after a single high exposure. Once sensitised, individuals mayexhibit asthmatic symptoms when subsequently exposed to atmosphericconcentrations well below the WES.
6.2.2
SAFE USE OF ISOCYANATES 17
6.3EFFECT ON EYES
6.3.1
Isocyanates in the form of vapour, aerosol, liquid or dust irritate the eyescausing watering and discomfort and can cause permanent damage. Inparticular, splashes from reacting foam represent a severe hazard to theeyes.
6.4EFFECT ON SKIN
6.4.1
Isocyanates have a mild tanning action on the skin. Occasionally contactdermatitis is produced as a manifestation of a specific skin allergy.
6.5HAZARDS FROM UNDESIRABLE REACTIONS
6.5.1WATER6.5.1.1
Isocyanates react slowly with water to produce carbon dioxide. While this isnot in itself a hazardous reaction, it can lead to the development of
dangerous pressures inside closed containers if the isocyanate becomescontaminated with water.
6.5.2RUBBER AND PLASTICS6.5.2.1
Isocyanates will attack and embrittle many plastic and rubber materials in ashort time. Others such as butyl rubber have a reasonable life span. Ifmaterials like butyl rubber are used, they must not be located in a positionwhere rupture would cause a large spillage and must be checked regularlyand replaced where necessary. Hoses of PTFE (Fluon or Teflon) suitablymetal braided on the outside must be used on high pressure machines.
6.5.3HEATING POLYURETHANE6.5.3.1
Thermal decomposition of polyurethane materials may lead to the evolutionof free isocyanate and a number of toxic gases, in particular carbonmonoxide and hydrogen cyanide. The temperature at which this occursvaries according to the type of polyurethane and the availability of oxygen.In general, polyurethane starts to decompose between 150° - 300°C.Hydrogen cyanide and carbon monoxide are evolved at approximately
500°C. Temperatures between 300° and 400°C have been found to cause theevolution of free isocyanate.
Tasks which may involve exposure to isocyanates due to the heating ofpolyurethanes include soldering wire coated with polyurethane plastic, “hot-wire” cutting of polyurethane foam, welding pipes lagged with polyurethanefoam and burning off polyurethane paint.
Refer to section 5.2 for details of reactions with particular chemicals.
6.5.3.2
18 SAFE USE OF ISOCYANATES
6.6HAZARD CLASSIFICATION AND SCALE OF OPERATION
6.6.1
The actual hazard associated with the use of isocyanates depends not onlyon the toxicity of the isocyanates, but also on their volatility and the quantityused in a particular operation. TDI is over 200 times more volatile than MDIat room temperature and thus the hazard posed by similar quantities of thesetwo materials is far greater for TDI. This means that safety provisions mustbe much more stringent for TDI. This is reflected in the requirements forTDI as compared to MDI in sections 7 and 8 of this code, where the
hazards are considered under two classes, a TDI class and an MDI class.Isocyanates with a high vapour pressure are considered to be in the TDIclass. These include TDI and HDI.
Isocyanates with a low vapour pressure are considered to be in the MDIclass. These include MDI itself, NDI, PAPI, IPDI, TMDI, and surface
coating materials (e.g. paints, lacquers) based on MDI. Appendix 1 containsfurther details of the various isocyanates.
Prepolymers for foaming processes, and surface coating materials containingpartially polymerised isocyanates (produced from TDI, HDI or mixtures ofthese with IPDI) are considered to be in the MDI class if they have levels offree TDI or HDI below 0.7%. However, if a surface coating is to besprayed, then for the purposes of respiratory protection the prepolymer isconsidered to be in the TDI class (see sections 9.4.7 and 9.5).
When materials in the MDI class are heated above a temperature of 50°Cthey shall be considered as materials in the TDI class. This is a generalityonly and may not hold in a particular case.
The scale of operation will be divided into three groups based on the
isocyanate usage rather than the amount of polyurethane material produced.When more than one operation exists in a factory, consideration would begiven to classifying the operations separately.
When the scale of operation is below 0.001 tonne (1 kg) of isocyanate perday and below 0.1 tonne (100 kg) of isocyanate per year, then the occupierwill be termed a low user of isocyanates.
When the scale of operation is greater than that of a low user and below 1tonne of isocyanate per day and 100 tonnes of isocyanate per year, then theoccupier will be termed a medium user of isocyanates.
When the scale of operation is above 1 tonne of isocyanate per day or above100 tonnes of isocyanate per year then the occupier will be termed a highuser of isocyanates.
6.6.26.6.3
6.6.4
6.6.5
6.6.6
6.6.7
6.6.8
6.6.9
SAFE USE OF ISOCYANATES 19
7. PLANT DESIGN
7.1GENERAL
7.1.1
All production plant shall be designed with the following criteria in mind:
(a)The system must not allow isocyanates to escape into the
atmosphere, and(b)As isocyanates will react with water under most conditions, every
attempt must be made to eliminate water, as both liquid and vapour,from the system.In all plant design and operation the current WES levels must not beexceeded. (See appendix 1.)
7.2VENTILATION
7.2.1GENERAL7.2.1.1
Buildings or rooms in which isocyanate materials are stored, handled orprocessed must have sufficient ventilation provided to ensure that therelevant WES is not exceeded at any time. Natural ventilation will providesome of the ventilation required but often this will have to be supplementedby mechanical extraction.
Extraction points shall be located as close to the point of potential hazard asis practicable. In areas of low air movement, regard must be had for the highdensity of isocyanate vapour, with extraction points being located nearground level.
Intake points shall be sited as far as practicable from outlet ducts to avoidrecycling of polluted air.
7.2.1.2
7.2.1.3
7.2.2 TDI7.2.2.1
Wherever practicable, totally enclosed systems shall be employed wheneverTDI class isocyanates, or other isocyanates heated above 50°C, are used.The addition and removal of these isocyanates from the systems should becarried out without the need to have any part of the process plant open tothe atmosphere.
Whenever opening of the above plant is unavoidable, such as for
maintenance, then sufficient additional ventilation shall be provided to keepvapour from isocyanates below the WES.
7.2.2.2
20 SAFE USE OF ISOCYANATES
.2.3MDI7.2.2.3
Ventilation units must be installed on or about the equipment when plant
design is such that vapours from TDI class materials could otherwise escapeinto the atmosphere.
7.2.2.4
Where hoods are required for TDI class materials then the following designprinciples must be applied (see figures 1 and 2):
(a)The process must be enclosed as much as possible;
(b)The extraction hood must be located as close as possible to the
source of the escaping vapour;(c)The hood face velocities must be sufficient to ensure that the WES
is not exceeded in the breathing zone of the operator. The actualrate of air movement required will depend upon the physical designof the booth and extraction equipment.(d)The vapours should be drawn away from the operator’s breathing
zone;(e)Baffles and side shields should be used to the fullest extent; and(f)
The hood should be positioned so that it does not interfere with theoperator’s work.
7.2.2.5
The ventilation system should be electrically or pressure interlocked so that itis impossible to start foaming (or other similar processes) with TDI classmaterials without the exhaust fans running. There should also be a timedelayswitch on all continuous foam processes which is so arranged that theventilation continues for at least half an hour after processing has ceased.Alternatively, permanent low-level ventilation should be supplied. This
equipment is essential for high users of TDI (i.e. those whose usage rate isabove 1 tonne per day or 100 tonnes per year) and is recommended forother users of non-trivial quantities.
7.2.3.1
Plant handling MDI class materials need special precautions only if there areoperations in which the material is foamed into open moulds and the WES isthus likely to be exceeded, or where there is a dust hazard from powderedisocyanates. However, if the reaction temperature during production of
MDI-based rigid foam exceeds 50°C, as is often the case, then enclosure ofthe process and effective ventilation of this enclosure will be essential.7.2.3.2
For MDI class materials a hood with a face velocity of 0.5 m/sec should belocated above these operations if this is practicable. Otherwise protectiveequipment must be worn.
SAFE USE OF ISOCYANATES 21
7EXAMPLES OF EXTRACTION HOODS FORTDI CLASS MATERIALS
22 SAFE USE OF ISOCYANATES
7.3DRUM HANDLING AND STORAGE
7.3.1GENERAL7.3.1.17.3.1.2
Drums should be placed on their sides, restrained from movement by suitablechocks, and stored in an area with adequate ventilation.
The handling and storage area may be either inside or outside the factory.Outside storage is recommended only for situations where drums do notremain outside for long enough to corrode.
Drums damaged in transit and found to be leaking must be isolated andtreated as a health hazard.
Any drum which has become pressurised must be isolated immediately andcovered. The pressure must be subsequently relieved as soon as possible bycarefully loosening the bung or drilling a small hole.
7.3.1.37.3.1.4
7.3.2TDI7.3.2.1
In order to thaw frozen drums of TDI they must be heated slowly using awell ventilated oven or hot chamber. The oven temperature shall becontrolled below 35°C. For prolonged storage the suggested maximum is30°C.
In no circumstances shall drums of TDI be thawed by using a naked flameor other forms of localised heating.
7.3.2.2
7.4DRUM EMPTYING
7.4.1GENERAL7.4.1.1
Isocyanates must not be displaced from drums by pressurising because ofthe problem of ultimate venting of the empty drum and the risk of anexplosion.
7.4.2TDI7.4.2.1
A gate valve, PTFE lined diaphragm valve or other valves in stainless steelor nylon should be fitted to the 50 mm diameter opening and an elbow of gaspiping containing gauze and dry silica gel should be fitted to the 20 mmdiameter opening. A drip tray containing solid decontaminant, e.g.
impregnated sawdust, should always be provided and adequate supplies ofliquid decontaminant should be available close to hand. (See appendix 3 forfurther information on decontamination mixtures.)
After the appropriate fittings have been made, small quantities of TDI classmaterials can be conveniently drawn off from a drum by placing it in ahorizontal position.
7.4.2.2
SAFE USE OF ISOCYANATES 23
7.4.2.3
To discharge appreciable quantities of TDI materials from a drum, it shouldbe stood end uppermost and a stand pipe introduced and secured through the50 mm diameter opening. A silica gel drier should be fitted over the 20 mmdiameter opening so that when the contents of the drum are discharged bypumping, the displacement is filled with dry air. Wherever possible, directdischarge into the reactor kettle or machine through flexible hosing and
suitable sealed connections is recommended so as to minimise the chance ofspillage.
7.4.3MDI7.4.3.1
Similar methods should be used for emptying drums of MDI class materialsexcept that the drip tray need not contain solid decontaminant. This methodis not necessary for polyurethane paints and lacquers.
7.5BULK STORAGE, TANKS AND LINES
7.5.1GENERAL7.5.1.1
All tanks in which TDI and MDI class materials (except polyurethane paintsand lacquers) are stored should be blanketed with a dry gas, such as
nitrogen, or with dry air or by locating a drying agent in the air vent. The airvent should be a conservation type which vents off to a safe area.In general, plain steel equipment is satisfactory for storing isocyanates. Atank may be lined with a heat cured phenolic coating to prevent
discolouration during storage. Linings will be unnecessary with carefulcontrol of moisture.
Stainless steel pipelines and tanks are perfectly satisfactory but their cost isnot warranted unless it is essential that the absolute minimum of colour bemaintained, as is the case in the production of clear coatings. However, thecleanability of bright finish type 316 stainless steel is excellent. This is
therefore recommended for connections that are sometimes exposed to theatmosphere.
Flexible hoses should be reinforced and valves used for handling TDI andMDI class materials should either be PTFE and/or nylon-lined. Stainlesssteel valves are also suitable and so is butyl rubber hose, provided it is usedno longer than six months as it hardens and will eventually crack.
7.5.1.2
7.5.1.3
7.5.1.4
7.5.2TDI7.5.2.17.5.2.2
Where TDI is heated by means of a heat exchanger, the temperature of theTDI shall be automatically controlled to no greater than 30°C.
To avoid the risk of over-filling, storage tanks for TDI class materials shouldhave the following instrumentation:
(a)A fully enclosed level gauge (magnetic type or float using level
tape preferred);
24 SAFE USE OF ISOCYANATES
(b) A temperature indicator; and(c) A high level alarm.
The use of a standard sight glass or manual dipping is prohibited.
7.5.2.37.5.2.4
Aluminium is not recommended for direct contact with TDI because of thepossible corrosion and subsequent contamination of the TDI.
If ambient temperatures require it, lines, valves and tanks containing TDIshould be lagged and heated by steam or electric tape trace to preventfreezing. After each use traced lines should be blown clear to preventoverheating and consequent discolouration provided the lines are self-draining. Otherwise it is better to leave the lines filled and turn off the traceheating. To avoid overheating, provision of suitable high temperature alarmsystems should be made.
Process vessels which are emptied and/or filled with TDI class materialsmust have their air vents extended out through the roof of the factory orsome other means must be used to prevent vapours escaping into the workarea. The vents should be designed in such a way that moisture does not getback into the process vessels.
A suitable cartridge type filter is desirable in the isocyanate supply line frombulk storage to the process.
7.5.2.5
7.5.2.6
7.6PUMPS AND FILTERS FOR TDI CLASS MATERIALS
7.6.1
Submersible glandless pumps shall be used to prevent leakage from glands.These pumps should also eliminate air entrainment which could adverselyaffect the process. A submersible pump should be immersed in a tank ofsuitably inert liquid (e.g. dioctyl phthalate) when it is not in use.Filters for TDI class materials should be drainable before opening andcapable of being cleaned from the top in order to prevent spillages.Down-draught ventilation adjacent to the filter is recommended.
7.6.2
7.7MOULDS
7.7.1
It is important that foam moulds should be adequately braced to withstandthe pressure arising from the foaming process when either TDI or MDIclass materials are used.
7.8STORAGE OF FOAMED MATERIAL
7.8.1GENERAL7.8.1.1
Newly-made hot foam slab stock must be stored in a separate well-ventilated area with fire resistant walls. It must not be moved to the otherprocess areas until the exothermic reaction has ceased and a reasonableamount of internal cooling has taken place. The time for this cooling period
SAFE USE OF ISOCYANATES 25
varies with the grade of foam. Therefore, newly-made foam blocks shouldnot be stacked or brought into contact with one another until an appropriatedegree of cooling is achieved.
7.8.1.2
Bulk stocks of polyurethane foam can burn quickly and rapidly, giving offvarious poisonous gases (e.g. carbon monoxide) and large amounts of hotdense smoke.
Self-contained breathing apparatus must be used in fighting this kind of fire.The temperature of the smoke and fumes from the polyurethane foam
creates an additional hazard. This danger is present regardless of whether ornot flame-retarded or flame-proofed foams are involved.
7.8.1.3
7.9DUST FROM CURED FOAM
7.9.1
Dust generated during the machining of foam blanks, provided they are fullycured, should not present a problem apart from the general nuisance dustpotential.
However, if it is still in the process of undergoing curing, foam must be
treated as if it contains free isocyanate and the appropriate precautions mustbe taken to ensure that no workers are exposed to hazardous levels ofisocyanate vapour.
7.9.2
26 SAFE USE OF ISOCYANATES
8. PLANT OPERATION,TRAINING AND SAFETY
8.1EMPLOYEE EDUCATION, TRAINING ANDRESPONSIBILITY
8.1.1
Employee training is probably the most important safety measure a companycan take. Although great efforts can be put into protective equipment,
operations and processes with safety in mind, an improperly trained personcan create an undue hazard; therefore, personnel involved with isocyanatesmust be given job training before being assigned to duties involving thehandling of isocyanates. This should cover the following aspects:
(a)the correct handling and storage of isocyanates;
(b)the hazards and symptoms of over-exposure to isocyanates;(c)the necessity of reporting early symptoms;
(d)the procedure to be adopted in the event of a spillage, suspected
leakage from valves, or suspected excess of isocyanates in theatmosphere;(e)first aid procedures (see section 9.2); and(f)
8.1.2
personal hygiene recommendations.
It is recommended that an advisory leaflet written in the operator’s firstlanguage covering the above points be given to employees at the completionof their job training. Appendix 4 gives an example suitable for translation.Because prompt action may be needed in an emergency, it is important thatprocess operators understand English or that supervisors can readilycommunicate with operators in their first language.
Induction training for personnel not directly concerned in the production ofpolyurethane material should mention the existence of hazards connectedwith the use of isocyanates. Isocyanate areas should be out of bounds tounauthorised persons.
All authorised visitors to the polyurethane process area must be warned ofthe hazard of isocyanates to any person with an asthmatic condition.Personnel must abide by the requirements of the code where applicable, e.g.by not smoking in no-smoking areas. They must also wear or use protectiveclothing and/or equipment supplied by employers under the code.
8.1.3
8.1.4
8.1.58.1.6
SAFE USE OF ISOCYANATES 27
8.2INFORMATION AND WARNING
8.2.18.2.2
Process areas where isocyanate exposure is likely to occur shall havewarning posters placed in prominent positions.
Signs shall be posted indicating the location of air respirators and/or airbreathing equipment.
8.3SPILLAGES
8.3.1
When spillages of isocyanate materials occur, there is the immediate risk thatthe concentration of isocyanate vapour in the atmosphere adjacent to thespillage will increase beyond the WES. Plans for handling spills must
therefore be drawn up which provide for the protection of those dealing withthe spillage and for the control and protection of other people in the vicinityso as to ensure that they do not suffer undue exposure.
Small spillages of MDI class materials (less than 1 litre) and very smallspillages of TDI class materials (less than 10 millilitres) can be wiped upimmediately with cotton waste (or treated with other absorbent material inthe case of MDI class materials) and the area treated with decontaminationmixture or isopropyl alcohol. The contaminated cotton waste (or absorbentmaterial) must be decontaminated as soon as possible. Gloves should beworn by personnel handling these materials.
Spills of TDI class materials which are more than a few millilitres and largespills of MDI class materials must be treated according to the generalprocedures outlined in appendix 2.
After spills in the category described under section 8.3.3, personnel must notbe permitted to return to the work area until air tests with appropriateequipment show the atmosphere to be below the WES.
A disaster plan shall be drawn up for accidents involving a major spillage ofTDI class materials. This must include provision for total plant evacuationand involvement of the necessary emergency services.
8.3.2
8.3.3
8.3.4
8.3.5
8.4WASTE DISPOSAL
8.4.1
Unreacted isocyanate shall not be disposed of under any circumstances andmust first be transformed into urea by reaction with water. Liquid isocyanatemust never be washed into a drain.
Isocyanate drums for disposal must be decontaminated and thoroughlycleaned before re-use or destruction. Methods of decontamination include:
(a)The use of decontamination mixture;
(b)Filling with water and leaving for 48 hours; and(c)The use of waste polyol.
Drums must be vented during or after these procedures.
8.4.2
28 SAFE USE OF ISOCYANATES
8.4.3
Returnable empty drums to be refilled with isocyanate should be completelydrained and all openings tightly closed with gaskets in place. Care should betaken that no moisture is present since this will react with traces of
isocyanate causing the generation of carbon dioxide, and the result could bethe rupture of the drum.
Disposal of waste materials after treatment should be in accordance withlocal authority requirements.
8.4.4
8.5EYE-WASH FACILITIES
8.5.1
Hygienic eye-wash facilities must be provided near the work area. Thesecan take the form of a small rose fitting connected by tubing to a tap, adevice which squirts water spray into the eyes when operated by thepressure of the forehead on a bar, or other suitable device. It isrecommended that high users provide safety showers and eye wash
facilities; that medium users provide eye wash facilities; and that low userssupply eye-wash bottles (see sections 6.6.7 to 6.6.9).
8.6RESPIRATORY PROTECTION
8.6.1
Administrative and engineering controls shall be used wherever feasible tomaintain isocyanate vapour concentrations below the prescribed WES level.Respirators that comply with the current standards shall be provided andused for non-routine operations, where occasional brief excursions above theWES occur, and for emergencies.
The principles governing the choice of respirators shall be as follows:
(a)TDI Class Materials
(i)
Compressed airline or self contained breathing apparatusrespirators are to be used in areas where the WES level islikely to be exceeded such as the hot box for TDI drums, andin the follow-up to any plant emergency including spills orleaks greater than 10 millilitres, or in cases where the extentof the spill or leak is in doubt.
8.6.2
(ii)Full facepiece type (negative pressure) gas respirators fitted
with the appropriate filter to remove organic vapours are
acceptable for cleaning up known small spillages (less than 10millilitres) provided workers’ safety is not compromised. Halffacepiece gas respirators with filters to remove organicvapours will be acceptable for the evacuation of otherpersonnel during plant emergencies.
NOTE: When not in use, gas respirators must be stored in sealed airtightcontainers or plastic bags to prevent the filters from deteriorating due toexposure to traces of fumes present in the atmosphere.
(b)MDI Class Materials
Full facepiece or half facepiece (negative pressure) gas respiratorsare acceptable in all situations except when spraying reacting foamor paint. In these cases full facepiece airline or self-containedbreathing apparatus respirators are to be used.
SAFE USE OF ISOCYANATES 29
8.6.3
Respirators shall be placed in marked locations close to, but not in, processareas and shall be routinely tested and adequately maintained. Records ofthe exposure time of canister respirators must be kept and the canisterchanged at the required intervals.
8.7PROTECTIVE EQUIPMENT AND CLOTHING
8.7.4
Protective equipment can he divided into 2 classes; normal protective
equipment and emergency protective equipment. These terms are defined asfollows:
(a)Normal Protective Equipment must be used with either MDI or
TDI class isocyanates during all working operations where there isadequate ventilation and hence no possibility of exposure toamounts of vapour in excess of the WES (see appendix 1). Thisshould include the following protective equipment:
Boiler Suit/Overall (heavy cotton types are preferred)Rubber or PVC Gloves where there is a risk of skincontamination; and
Goggles or Face Shield where there may be a risk of eyehazards.
(b)Emergency Protective Equipment must be used with both TDI
and MDI and isocyanate containing products wherever there is arisk of exposure to concentrations of vapour (or dust) in excess ofthe WES. Such conditions occur when:
(i)
TDI is handled outside a properly ventilated area;(ii)MDI is handled, heated, sprayed or involved in mixinghead
cleaning operations outside a properly ventilated area; or(iii)Pure MDI is handled in solid form and there is a risk of dust
being created or raised.Typical items of emergency protective equipment include:
Waterproofs suitRubber or PVC glovesRubber or PVC apronRubber boots and
Full-face breathing apparatus
8.8CLEANING AND REPAIR OF TANKS AND ASSOCIATEDEQUIPMENT USED FOR THE MIXING AND STORAGE OFISOCYANATES
8.8.1
Authorisation: The cleaning of lines and tanks used for isocyanates willexpose personnel to a greater hazard risk than normal operations. These
30 SAFE USE OF ISOCYANATES
procedures must be carried out on the authorisation of a work permit issuedby the factory manager or his nominee only. The person responsible mustalso be satisfied that the work is carried out under the direction ofappropriately trained personnel who are familiar with the necessaryprocedures and safeguards.
8.8.2
Work Permit: A written work permit which covers the following elementsshall be prepared:
(a)Work shall not he carried out by an unaccompanied person;(b)Isolation procedure must eliminate electrical and mechanical
hazards;(c)Decontamination procedures must remove residual isocyanates left
in the system;(d)Atmospheres in confined spaces must be tested to ensure the air is
safe to breathe;(e)Unless airborne concentrations of isocyanates can be maintained
below the appropriate WES, respiratory protection must be used;(f)
Adequate access and egress to and from confined areas must beprovided; and
(g)Adequate rescue procedures must be established and suitable
rescue equipment must be provided.See appendix 5 for an example of a work permit.
8.8.3
On completion of the work the authorising officer shall sign the permitconfirming that the plant is safe for use in process operations.
SAFE USE OF ISOCYANATES 31
9. MEDICAL REQUIREMENTS
9.1EMPLOYEE MEDICAL SURVEILLANCE
9.1.1
9.1.2
9.1.3
9.1.4
9.1.5
9.1.6
9.1.7
32 SAFE USE OF ISOCYANATES
One of the early symptoms of isocyanate-induced respiratory illness is a drycough, characteristically worse in the evening or at night, often obscuring thefact that it is due to the work environment. It is therefore necessary to takethe following steps to protect the health of isocyanate workers.
Isocyanate users should arrange for a pre-placement health examination tobe carried out on all employees who will be working with TDI classmaterials, or MDI class materials which are sprayed. This examinationshould be used to provide baseline medical data and to detect possiblysusceptible individuals who should be advised against working withisocyanates. This health examination should include a review of the
employee’s medical history and, wherever possible, lung function tests. Thehealth history review and lung function tests should be repeated within threemonths of beginning work with isocyanates.
Following the initial examinations, medical history reviews and lung functiontests should be performed at least annually on all employees working withTDI class materials and MDI class materials which are sprayed.
All isocyanate users should arrange for a health examination, as described insection 9.1.3 to be carried out on any employee who experiences a coughlasting longer than four weeks, or a chest illness requiring an absence of twoweeks or more from work.
If an unexplained fall in lung function is found, the work environment of theaffected employee should be investigated and any employee showingrespiratory distress, should not return to work with isocyanates. The lungfunction measurement should be repeated the next day and, if the diagnosisis confirmed, the employee should not return to work with isocyanates untilcleared by a further medical examination.
The medical diagnosis of true sensitisation to isocyanates at any time mustpermanently exclude that person from further exposure to isocyanatematerials.
NOTE: This does not preclude such people from being employed elsewherein the factory where isocyanate exposure can be avoided.
After accidental over-exposure, such as after a spillage of either TDI orMDI class materials, all employees involved should have an examination (asdescribed in section 9.1.3) two to four weeks after the incident so as todetect any harmful effects.
9.1.89.1.9
Smoking shall not be permitted where isocyanates are stored or used.Records of the medical examinations and health surveillance checks
mentioned in sections 9.1.2-4 and 9.1.7 should be kept by the firm and madeavailable to the departmental medical practitioner or nominee. These recordsshould be held for a period of at least 7 years after the employee hasterminated employment with the firm.
9.2FIRST AID
9.2.1
When it is known or suspected that workers have been exposed to
isocyanate vapour levels above the WES, they should be removed from thecontaminated area. Provided only limited exposure has occurred, only thosesteps described in section 9.1.7 need be carried out. However, it should beremembered that symptoms may not develop until many hours after suchexposure.
If the exposure was severe and the worker has stopped breathing, theworker should be moved to an uncontaminated atmosphere and artificialrespiration started immediately. The patient should be kept warm and shouldreceive medical attention without delay.
9.2.29.2.3
In high-user establishments oxygen should always be available for use inemergencies by experienced personnel.
Splashes of isocyanate in the eye are irritant and may cause severe chemicalconjunctivitis. If any chemical used in the foaming process enters the eyes,they should be irrigated with copious amounts of clean water for at least15minutes as soon as possible. It has been found that this will require thehelp of another person to hold the victim’s eye open. Reacting foam isparticularly dangerous if it enters the eye.
Contact lenses should be worn only if the eyes are covered with goggles or aface shield when working with isocyanates. Chemicals can get behind
contact lenses and irreparable damage may occur to the eye while the lens isbeing removed prior to the irrigation required in section 9.2.3.
If appreciable amounts are swallowed, the affected person should be givenbetween 250 and 500m1 of milk or water. Do not induce vomiting. Obtainmedical attention as soon as possible. Small splashes accidentally swallowedshould present no hazard. DO NOT give anything by mouth to anunconscious person.
It is important that any isocyanate spilled on the skin should be removedimmediately by washing with soap and water, as isocyanates can causedermatitis, and may cause sensitisation leading to dermatitis in a smallnumber of individuals.
NOTE: If skin contact is extensive, the employee should immediately use theemergency shower if available or adopt some other method of achieving athorough cleansing of the affected area (see section 8.5). With TDI classmaterials this is important because of the inhalation hazard. Solvents maycause dermatitis and should not be used.
9.2.4
9.2.5
9.2.6
SAFE USE OF ISOCYANATES 33
9.2.7
Spillage onto the employee’s clothing is also serious with TDI class
materials, particularly because of the inhalation hazard. The affected personshould enter the shower immediately and remove the contaminated clotheswhile under the shower. Changes of clothing should be provided for such anemergency.
9.3ATMOSPHERIC TESTING FOR ISOCYANATES
9.3.1
9.3.2
9.3.3
9.3.4
9.3.5
9.3.6
9.3.7
34 SAFE USE OF ISOCYANATES
It is necessary for high and medium users of TDI class materials and MDIclass materials which are sprayed to take regular atmospheric
measurements and to check that the ventilation system in the productionarea is working adequately.
The testing points for atmospheric measurements should be determined as aresult of use experience. For example, in a plant producing flexible foamcontinuously the most likely points would be:
(a)foaming head platform - particularly in the breathing zone of the
foaming head operator;(b)side paper strip off;(c)base paper strip off; and(d)at the cutting point of the blocks.
The tests should also be carried out when the concentration is likely to be atits highest level. For example, in plant producing flexible foam continuously,the isocyanate concentration increases throughout the foaming operation andthe highest concentration is found just after foaming has stopped (seesection 7.2.2.5).
All high users of TDI class materials should operate a continuous TDI
analyser (see Sections 9.3.6-9). The output recorded by the analyser shouldbe held in such a place that it is available to employees and torepresentatives of OSH.
Medium users of TDI class materials should carry out tests at least once aweek during operations and low users at least twice a year (forrecommended methods see sections 9.3.6 to 9.3.9). If ambient airconcentrations of isocyanates reach half the WES in either case, more
frequent tests should be carried out. The results of all tests should be held insuch a place as to be available to employees and to representatives of OSH.Detector tubes can be used to measure aromatic isocyanates (but not MDI)and are recommended for use by low users or for checking that the WES isnot exceeded in an area after spillage has been decontaminated.
Colorimetric methods are available for testing aromatic TDI class materials(including MDI). These are:
(a)the ICI method utilising paper colour comparison; and(b)the Marcali method utilising liquid absorption.
These methods are recommended for use by medium users. Special methodsare required when testing for aliphatic isocyanates.
9.3.89.3.9
Continuous analysers, which are capable of detecting both aromatic andaliphatic (e.g. HDI) isocyanates, should be used by high users.Monitors for checking on personal exposure levels may be useful forinvestigating the individual work habits of those demonstrating possiblesymptoms.
With all users, if the WES is exceeded, an investigation must be carried outin order to find and correct the cause. Sampling must be repeated each timethe isocyanate is used until the atmospheric release has been controlled.No employee shall be allowed to remain in an area contaminated withisocyanate above the WES, unless wearing suitable respiratory protectiveequipment. In the event of an evacuation as the result of such an excess,further readings must be taken before personnel are allowed to return to theplant.
A register of results for all tests (including both positive and negative
Detector tests) should be maintained. The action taken as the result of theWES being exceeded should be noted along with the names of the personnelexposed. This register should be retained for at least 12 months and shouldbe made available to employees and representatives of OSH.
There shall be no requirement on the occupiers of spray painting premises tocarry out any of the monitoring tests provided for in sections 9.3.1-12. Thisis because it is recognised that the WES will normally be exceeded in allspraying operations and therefore special precautions are required to protectworkers (see section 10.4). Isocyanate monitoring, however, may be carriedout periodically by OSH in a wide range of spray booths to maintain a checkon the general degree of hazard present in the workplace.
9.3.10
9.3.11
9.3.12
9.3.13
9.4CONTAMINATED DISCHARGES
9.4.1
Legislation relating to the discharge of contaminates into the atmosphere oronto land or water is administered by regional authorities and generallyprohibits such activity (refer appendix 9).
Isocyanates readily form ureas in the presence of water and therefore waterscrubbers attached to the exhaust ventilation system offer a useful controlmethod. Water scrubbers are recommended for high users of TDI classmaterials. Alkali solutions are more effective than water and hence willincrease scrubber efficiencies. Care must be taken to ensure that the use ofwater scrubbers to control emissions to the air does not give rise to thedischarge of contaminants into waste water.
If firms are in any doubt concerning emissions or control equipment, theregional council shall be consulted.
9.4.2
9.4.3
9.5LABELLING
9.5.1
All containers of isocyanates or products containing isocyanates should beclearly labelled (refer appendix 9).
SAFE USE OF ISOCYANATES 35
10. APPLICATION OF POLYURETHANEPAINTS AND LACQUERS
10.1GENERAL
10.1.1
Polyurethane paints and lacquers fall into the following categories:
(a)urethane oils and urethane alkyds (e.g. polyurethane varnishes);(b)blocked isocyanates (e.g. some soldering fluxes); and(c)polyisocyanates (e.g. one-pack moisture-cured and two-pack
isocyanate-containing paints).
10.2URETHANE OILS AND ALKYDS
10.2.1
In the case of the manufacture of urethane oils and alkyds, the standardprecautions set down elsewhere in this code for the handling of freeisocyanates must be observed. However, the final product contains noresidue of free unreacted isocyanate and thus in the handling and use ofthese products no special precautions are necessary.
10.3BLOCKED ISOCYANATE COATINGS
10.3.1
Blocked isocyanate coatings also contain no residue of free unreactedisocyanate, and thus the application of these materials poses no problemsfrom that viewpoint. However, phenolic solvents may be present in theformulated paint and additional phenolic material may be released duringheat curing processes. In these circumstances appropriate precautions forphenols must be taken. These must include protection (adequate ventilationand/or respiratory protection against inhalation of phenoliccontaining vapoursand suitable protective clothing to prevent skin contact.
10.4POLYISOCYANATES: APPLICATION BY SPRAY, BRUSHOR ROLLER
10.4.1
The great majority of industrially-used polyurethane coatings contain
polyisocyanates and thus fall into category 10.1 (c) above. The remainder ofthis section is concerned with precautions to be observed in the handling andapplication of these materials.
36 SAFE USE OF ISOCYANATES
10.4.2
MDI type paints are those paints based on polyisocyanates which containless than 0.7% free TDI or HDI. These products are predominantly used inspray painting applications,
TDI type paints are all those paints containing more than 0.7% free TDI orHDI. They are usually designed for special-purpose applications.
Mixing of Paints. Both MDI and TDI class paints shall be mixed in
wellventilated areas. The appropriate respiratory protection should be worn,as stated in section 10.4.6.
Where a spillage of an MDI class paint or lacquer occurs, the spillage shallbe cleaned up immediately by spreading sawdust, sand or similar materialover the spillage and placing the collected mixture in an outside bin. Thearea affected by the spill should be decontaminated with a solution of diluteammonia and detergent or other decontaminating mixture (see appendix 3).Spillages of TDI class paints shall be treated as detailed in appendix 2.
10.4.310.4.4
10.4.5
10.4.6 APPLICATION BY BRUSH OR ROLLER10.4.6.1Where MDI class materials are applied by brush or roller, there is unlikely to
he a problem from exposure to free isocyanates unless ventilation in the areais inadequate. In this latter situation, protection can be obtained by use of anon-nasal respirator fitted with the appropriate canister(s).10.4.6.2Where TDI class materials are applied by brush or rollers the area shall be
well ventilated and on-nasal canister respirators worn. However, if there isdoubt about the effectiveness of the ventilation then positive pressureairsupplied respirators must be used.
10.4.7 APPLICATION BY SPRAYING10.4.7.1The atomised liquid paint which emerges from a spray gun is in the form of a
fine mist and is technically referred to as an aerosol. These aerosols are of asufficiently small particle size that they can be inhaled, and also the increasein the surface area of the paint following atomisation results in an increase inthe isocyanate vapour being evolved. In addition, spraying applicationspresent a major hazard from isocyanate-containing paints when the aerosolwhich bounces back off the sprayed article enters the breathing zone of theoperator. Therefore, the spraying of isocyanatecontaining paint represents aconsiderably increased hazard over the application of these materials bybrush or roller.10.4.7.2A further factor to be considered is that the aerosols of some polyurethane
paints may contain a substantial quantity of isocyanate prepolymer havingunreacted isocyanate groups. The potential of these prepolymers to causerespiratory sensitisation and irritation is now considered, following recentresearch findings, to be no different from that of the free isocyanatemonomer.10.4.7.3Because of the matters discussed in sections 10.4.7.1 and 10.4.7.2 it is clear
that the difference in volatility (and therefore in hazard) between MDI class
SAFE USE OF ISOCYANATES 37
and TDI class polyurethane paints ceases to be of importance when thesematerials are applied by spraying, and thus the two classes of paints must betreated identically in terms of the hazard posed when they are sprayed.
10.4.8 PRECAUTIONS TO BE ADOPTED FOR SPRAYING AND DRYING OFSPRAYED ARTICLES10.4.8.1Unless otherwise provided for in this code, all spraying and the drying of
sprayed articles shall be carried out in accordance with the requirements ofthe Regulations.10.4.8.2The spraying of all isocyanate-containing paints must be carried out in a
properly designed and constructed spray booth in which the air movement isprovided by mechanical ventilation in accordance with section 10.4.8.3. Theonly exceptions to this requirement shall be those outlined in section 5.Tunnel booths or canopy booths provided with an up-draught air movementshall not be used for the application of paints containing isocyanates.10.4.8.3All spray booths shall be designed and installed so that they are capable of
producing and maintaining within an empty room booth or at the workingopening of a cabinet booth the air movement stipulated below:
(a)All booths including semi down-draught booths shall provide a
uniform air movement of not less than 0.5 m/sec within thebreathing zone of the operator. or(b)In the case of a full down-draught booth, the minimum average
downward air movement shall be not less than 0.20 m/sec and, inaddition, no single grid position within the booth shall have a
downward air velocity of less than 0.10 m/sec (see appendix 5 formethod adopted by OSH for determining air movements).NOTE: If more than one spray gun is installed or used in any spray booth,the air movement to be provided may need to be increased. Advice must beobtained from the nearest office of OSH.
10.4.8.4The mechanical ventilation (fan belt driven) system provided must be
interlocked with the air supply to the spray gun in such a manner as toensure that the gun cannot be operated unless the mechanical ventilationsystem is in operation and producing and maintaining the air movementrequired by section 10.4.8.3. In the case of ventilation, fans driven directlyoff the motor shaft or via a gearbox an electrical interlock between the spraygun and the fan motor will suffice.10.4.8.5When operators whether spraying or not, are required to work inside a spray
booth whilst spraying is in progress they shall wear one of the following
types of airline respirator, a full facepiece type, or a half facepiece type withseparate goggles, or a hood or helmet type to protect them from inhaling theisocyanate monomer and prepolymer in aerosol form.10.4.8.6The compressed air supply for the respirators must be taken from an
uncontaminated source and be substantially free of carbon monoxide and
38 SAFE USE OF ISOCYANATES
carbon dioxide. The supplied air shall be free from all odour and filtered toremove water, dust and oil mist. It is recommended that an alarm systemshould be fitted to the air-supply unit to warn the user whenever the pressurefalls to the minimum safe level. (See appendix 6 for requirements for allcompressed air systems.)
10.4.8.7In addition to the recommended respiratory and eye protection (see section
10.4.8.5), spray operators shall wear overalls, gloves and a head covering inthe case of respirators which leave the hair exposed.10.4.8.8Mechanical ventilation of the booth must be maintained after spraying
ceases. until the work area is free of all residual spray mist. No personshould enter the booth unprotected for at least 5 minutes after sprayingceases.10.4.8.9Positive-pressure spray room booths have the capability of providing a dust-free environment by ensuring no unfiltered air can enter the booth. Tominimise the possibility of toxic vapours escaping, all entrances to thesebooths must be hermetically sealed. As an additional precaution, it is
recommended that the over pressure within the booth be maintained at nomore than 25 Pa. Neutral or negative-pressure booths are inherently saferand are preferred.10.4.8.10When small cabinet booths are used for operations such as the spraying of
test samples and the inward air velocity has been increased to 1 m/sec ormore, respiratory protection may not be necessary, provided no spray bounceback can occur. However, it is recommended that respiratory protection beprovided and worn.10.4.8.11In all other cases where objects are being sprayed in cabinet booths and
spray bounce back cannot be effectively controlled even at air velocities of1m/sec, or where the operator may need to partially enter the booth, he orshe must wear an airline respirator. In these situations an air movement rateof 0.5 m/sec is acceptable.
10.5SPRAYING OPERATIONS OUTSIDE OF SPRAY BOOTH
10.5.1
Where the regulations allow for objects to be sprayed outside of a spraybooth then, the whole of the enclosed area shall be regarded as hazardousand respiratory precautions must be taken as detailed in sections 10.4.8.5-8.Warning signs shall be posted to prevent unauthorised personnelinadvertently entering the hazardous area.
Where spraying is carried out in the open air, all persons working within15metres of the spraying operation must be provided with and wear
respiratory protection as detailed in sections 10.4.8.5-7. Warning signs shallbe posted to prevent unauthorised personnel inadvertently entering thehazardous area.
10.5.2
SAFE USE OF ISOCYANATES 39
10.6CONSTRUCTION MATERIALS FOR SPRAY BOOTHS ANDDRYING OVENS
10.6.1
The design, construction and construction materials used in any spray booth,combination spray and drying booth, and any drying oven used for theapplication and drying of articles coated with TDI or MDI class materialsshall be in accordance with the requirements of the Regulation , or asalternatively specified in appendix 8.
10.7ISOCYANATE OVER-EXPOSURE
10.7.1SYMPTOMS10.7.1.1Vapours and spray mists containing free isocyanates are highly irritating to
the eyes and respiratory tract, and may cause inhalation sensitisation. In
sensitised persons even minute isocyanate concentrations may lead to severeasthmatic attacks. Respiratory effects may be delayed for several hours.The liquid may be irritating to the skin and cases of skin sensitisation havebeen reported,10.7.1.2Atmospheric over-exposure may lead to the following symptoms:
(a)sore eyes (conjunctivitis),(b)running nose (rhinitis),(c)sore throat (pharyngitis),(d)coughing (bronchitis),(e)wheezing, tight chest (asthma),(f)
fever, breathlessness and cough (pneumonitis).
10.7.2FIRST AID TREATMENT10.7.2.1Inhalation
This may be either from the vapour or from an aerosol. Remove theaffected person to fresh air. Keep at rest. Obtain immediate medicalattention.
10.7.2.2Eye Contact
If isocyanate has entered the eyes, flush them immediately with direct mainswater or sterile water from an eye wash bottle for at least 15 minutes,holding the eyelids apart. Obtain immediate medical attention.
10.7.2.3Skin Contact
Wash the skin immediately with copious amounts of water and soap (ifavailable). Remove heavily contaminated clothing immediately. Obtainmedical attention if skin dermatitis appears. (Clothing should be
decontaminated in an aqueous solution containing 2%-5% ammonia (SG0.880) and 0.2%-0.5% liquid detergent for one hour and then launderedbefore re-use.)
40 SAFE USE OF ISOCYANATES
10.7.2.4Ingestion
DO NOT induce vomiting. If the person is conscious, give between 250 mland 500 m1 of milk or water to drink. Take to hospital without delay.DO NOT give anything by mouth to an unconscious person.
10.8EMPLOYEE TRAINING
The training of painters using isocyanate-containing paints is an importantsafety measure which must be undertaken by every employer. Theinstruction and training must include the following aspects:
(a)The hazards and symptoms of over-exposure to isocyanates (see
section 10.7.1).(b)The necessity for wearing an airline respirator and other protective
clothing during all spraying operations (see sections 10.4.7.1-3,10.4.8.5. and 10.4.8.7).(c)The procedures to be adopted in the event of a spillage (see
section 10.4.5).(d)First aid procedures (see section 10.7.2).
(e)The correct use and maintenance of respirators including their
storage.(f)Safe work procedures, methods and practices.
(g)The reporting of defects in safety devices and equipment.
10.9REMOVAL OF POLYURETHANE PAINT
10.9.1 SANDING DOWN10.9.1.1When isocyanate paints are fully cured, i.e. have been applied for more than
24 hours at room temperature or heated for one hour at 70 °C, and aresanded down, the dust produced will not present an isocyanate hazard. Thisis because fully cured paints contain no free isocyanates. In such instances adust mask should be worn to provide protection from the general nuisancedust present. Where new paint that may not be fully cured is sanded down,the dust will contain free isocyanates. A particulate respirator fitted withClass H filters, or an airline respirator should be worn. Where practical theuse of wet sanding methods is recommended as a means of reducing theamount of dust generated.
10.9.2 WELDING/CUTTING OF PAINTED METAL10.9.2.1In panel beating operations where metal previously painted with isocyanate-containing paints is subject to an oxyacetylene or gas torch, the polyurethanepaint will decompose and produce a number of toxic gases including carbonmonoxide. Free isocyanates should not be formed or if they are only in suchminuscule amounts that no specific precautions will be required. In this
SAFE USE OF ISOCYANATES 41
respect polyurethane paints differ significantly from polyurethane foams (seesection 6.5.3). However, the metal cutting operation itself will normallyproduce hazardous fumes and must be performed in a well ventilated area.Where there is any doubt concerning the effectiveness of the ventilation,workers must wear respiratory protection such as an airline respirator.
10.10 EMPLOYEE MEDICAL SURVEILLANCE
10.10.142 SAFE USE OF ISOCYANATES
One of the early symptoms of isocyanate-induced respiratory illness is a dry
cough, characteristically worse in the evening or at night, often obscuring thefact that it is due to the work environment. It is therefore necessary to takethe following steps:
(a)Occupiers involved in spraying surface coatings containing free
isocyanates or polyisocyanates must ensure that new employeesare advised to undergo a preplacement health examination. Thisexamination should be used to provide baseline medical data and todetect possibly susceptible individuals, who should be advisedagainst working with surface coatings which are sprayed andcontain free isocyanates or polyisocyanates. This health
examination should include a review of the employee’s medicalhistory and lung function tests. The health history review and lungfunction tests should be repeated within 3 months of beginningwork.(b)Following the initial examinations, medical history reviews and lung
function tests should be performed at least annually on allemployees.(c)Occupiers should also arrange for a health examination, as
described in paragraph (b) to be carried out on any employee whoexperiences a cough lasting longer than 4 weeks, or a chest illnessrequiring an absence of 2 weeks or more from work.(d)If an unexplained fall in lung function is found, the work
environment of the affected employee shall be investigated andany employee showing respiratory distress must not return to workwith surface coatings containing free isocyanates or
polyisocyanates. The lung function measurement should berepeated the next day and, if the diagnosis is confirmed, the
employee shall not return to work until cleared by a further medicalexamination.(e)The medical diagnosis of true sensitisation to isocyanates at any
time must permanently exclude that person from further exposureto isocyanate materials.
NOTE: This does not preclude such people from being employedelsewhere in the premises where isocyanate exposure can beavoided.
(f)
Records of the medical examinations and health surveillance
checks mentioned in paragraphs (a) (b) and (c) should be kept bythe firm and made available to the departmental medical
practitioner or nominee. These records should be held for a periodof at least 7 years after the employee has terminated his/heremployment with the firm.
10.11 ISOCYANATE MONITORING
10.11.1
It is acknowledged that the free isocyanate concentration present in theaerosol mist during spray painting in a correctly set up and operated boothwill usually exceed the Workplace Exposure Standard. For this reason,worker protection must be guaranteed by wearing a full facepiece airlinerespirator or its equivalent (see section 10.4.8.5) and routine isocyanatemonitoring is unnecessary. Isocyanate monitoring, however, may be carriedout periodically by OSH the in a wide range of spray booths to maintain acheck on the general degree of hazard present in the workplace.
10.12 LABELLING
10.12.1A specific warning statement is required on all two-pack polyurethane and
moisture-cured products to be applied by spray.
WARNING: The following references, standards and associated informationhave been updated at the time of publication, however, it is subject to changewithout notice at any time.
SAFE USE OF ISOCYANATES 43
APPENDIX 1: WORKPLACEEXPOSURE STANDARDS
44 SAFE USE OF ISOCYANATES
WES refer to airborne concentration and are divided into three categories:
(a)WES — Time Weighted Average (TWA) — the time weighted
average concentration for a normal 8 hour workday or 40 hourworkweek, to which nearly all workers may be repeatedly exposedwithout adverse effects;(b)WES — Short-Term Exposure Limit (STEL) — the maximal
concentration to which workers can be exposed for a period up to15 minutes provided that no more than four exposures per day arepermitted, with at least 1 hour between exposure periods, andprovided the daily TWA also is not exceeded; and(c)WES — Ceiling (WES-C) — the concentration that should not be
exceeded even instantaneously.WES should not be regarded as marking a boundary between safety anddanger. Because of a wide variation in personal susceptibility some workersmay experience discomfort at levels well below the WES. Therefore, thelevel of any airborne contaminant should be reduced to the lowestpracticable level below the WES.
Isocyanates and their workplace exposure standards 1992.
The Workplace Exposure Standard for all isocyanates including prepolymersis:
WES - TWA0.02 mg/m3 (as -NCO)WES - STEL
0.07 mg/m3 (as -NCO)
A person who has developed sensitivity to isocyanates should not be exposedto them in any concentration at any time.
APPENDIX 2: SPILLAGE
PROCEDURE
1.Put on emergency equipment (see section 8.7.1(b)).2. Cover spillage with absorbent material such as sawdust.
3.Pour on decontaminant mixture* in a quantity estimated to be twice thevolume of the spill.4. Allow at least 10 minutes for decontaminant to react.
5. Collect all residues from the spillage and place them in an open container.6. Add further decontaminant mixture to this material, place a loose coverover the container and remove it to a safe place. Discard residues afterone day. (See section 8.4).7. Wash down the area with liquid decontaminant.8. Rope off the area and post “No Smoking” signs.9. Clean and decontaminate safety equipment.
* The decontaminant mixture used will depend on the circumstances (seeappendix 3). Flammable decontaminant mixtures though more efficient cannotbe used close to unprotected electrical equipment. It may also be necessary touse a cold weather decontaminant mixture. A “No Smoking” sign is notnecessary with the non-flammable decontaminant mixture.
SAFE USE OF ISOCYANATES 45
APPENDIX 3:
DECONTAMINATIONMIXTURES
1.Fast Acting but Flammable Liquid Decontaminant(a)Industrial Alcohol (denatured ethanol,methylated spirits or isopropyl alcohol)(b)Water
(c)Conc. Ammonia Sol. (sg 0.88)
2.Slow Acting Non-Flammable Liquid Decontaminant(a)Water
(b)Nonionic Surfactant (100%)(c)Conc. Ammonia Solution (sg 0.88)3.Solid Decontaminant(a)Sawdust
(b)Keiselguhr, technical (or china clay or Fuller’s earth)(c)
Breakdown solution
The breakdown solution for the solid decontaminant can
be the same as the non-flammable liquid decontaminant above,or as follows:
(a)Ethanol(b)Triethanolamine
(c)Conc. Ammonia Solution (sg 0.88)(d)Water
(e)Dyestuff (water sol.)
4.Cold Weather Decontaminant(a)Isopropyl Alcohol(b)
Perchloroethylene
46 SAFE USE OF ISOCYANATES
50% by wt.45% by wt.5% by wt.
90% by vol2% by vol8% by vol20% by wt.40% by wt.40% by wt.50% by wt.10% by wt10% by wt.29.5% by wt.0.5% by wt.
50% by wt.50% by wt.
APPENDIX 4: SAMPLEHANDOUT SUITABLEFOR TRANSLATION
1.DO wear the protective clothing that your supervisor asks you to wear.
DO NOT get careless with chemicals.2.DO move out of the work area quickly if there is a spillage.
DO NOT attempt to clear the spillage up.
3.DO avoid getting the chemical on your skin or clothes.
DO NOT ignore splashes on your skin, wash them off at once with soapand water.4.DO wash yourself when you leave the work area.
DO NOT keep food or eat or drink in the work area.
5.DO report to your supervisor if you think you can smell the chemical.
DO NOT ignore a valve that leaks. Report it to your supervisor.6.DO report to the clinic or your supervisor if your breathing is affected.
DO NOT neglect splashes in the eye. Wash them out at once and report toyour supervisor or clinic.
SAFE USE OF ISOCYANATES 47
APPENDIX 5: SPECIMENWORK PERMIT
Work Permit No: ______________________________Priority (ABC) Cost Code: ________________________Date presented: ________________ Time: ________________ Date required: ________________Item - Details of work requested or explanation of problems with unit: __________________________________________________________________________________________________________________________________________________________________________________________________________________Estimated man-hours required: _______________________________________________________________Estimated material costs: _________________ Total estimated cost: _________________________________Spare parts required: _______________________________________________________________________Approval to proceed given by: _________________________ Date: __________________________________
CLEARANCE CERTIFICATE
PRECAUTIONS NECESSARY TICK STEPS TAKEN TO ISOLATE ISOLATED BY DATE YES NO (LONG HAND)Electrical isolationChemical isolation: Liquid,vapours, dustSteam isolationGas isolation Arc weldingOther
Protective equipment required: Gloves, spectacles or goggles, respirator, long-distance breather, face shield orchemical hood, apron, footwear, helmet, harness, firefighting, special lighting, stand-by attendant.
Other precautions (state): ____________________________________________________________________Precautions necessary checked by: ______________________________ Date: __________ Time: _________Approval to proceed given by: ___________________________________ Date: ________________________The above work has been undertaken by the following personnel who have been instructed in the correct safetyprocedures and work methods to be adopted:
____________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ (Signature of person in charge)
Work commenced : Time: _____________ Date: _____________ To be completed by engineering supervisorWork completed : Time: _____________ Date: _____________
Materials used: _______________________________ Total man-hours on job: ________________________
Materials cost: ______________________________
Spare parts used: _____________________________ Spare parts costs: ____________________________
48 SAFE USE OF ISOCYANATES
APPENDIX 6: REQUIREMENTS
FOR AIR QUALITY(COMPRESSORS OR
CYLINDERS) FOR SUPPLIED
AIRLINE RESPIRATORS
1. AIR SUPPLY
The necessary capacity of any air service (i.e. compressor) for personal
protection shall be calculated on a minimum requirement of 300 litres per minutefor the first person and at least 170 litres per minute for each subsequentperson.
Air used to supply respirators shall:(a)have no objectionable odour; and
(b)contain not less than 19.5 percent and not more than 22 percent by
volume of oxygen. Additionally, at 15 °C and 100 kPa absolute the airshall:
(i)contain not more than 11 mg/m3 (10 p.p.m. by volume) of carbon
monoxide;(ii)contain not more than 1400 mg/m3 (800 p.p.m. by volume) of
carbon dioxide;(iii)contain not more than 1 mg/m3 (1 p.p.m. by volume) of oil;(iv)for cylinders, contain not more than 100 mg/m3 of water when
sampled from a cylinder initially filled to a pressure of at least12MPa.
1.2 AIR TEMPERATUREAir supplied from a compressor to a facepiece, hood or helmet should be at acomfortable breathing temperature within the range 15 to 25°C.
1.3 AVOIDANCE OF STALE AIR OR MOISTUREArrangements should be made to avoid the pocketing of stale air in pipelines.The use of ring circuits and controlled draining helps to guard against thehazard.
SAFE USE OF ISOCYANATES 49
Couplings should be of the “snap type” and should be of different design tothose used for other compressed air services.
Provisions should also be made, at appropriate places, to drain away water fromany pipeline. Water traps should be drained prior to using the apparatus.
1.4 WARNING DEVICEWhere an ‘in line’ auxiliary (secondary) air supply has not been provided toguard against primary supply failure, the user of an air-supplied respirator shallbe warned by an automatic device whenever an inadequacy in the air supplymay represent an immediate hazard to the user.
1.5 COMPRESSORSSystems shall incorporate a receiver of sufficient capacity to reduce pulsationsfrom compressor action and reduce compressor overheating. Compressors shallbe well maintained and shall not be allowed to run hot, as harmful substancesmay be produced by the decomposition of the lubricating oils. Filters should bepurged or replaced at regular intervals in accordance with the manufacturer’sinstructions. Consideration should also be given to the use of oil-freecompressors.
The air intake to the compressors should be sited in an uncontaminated
atmosphere. Particular care should be taken to ensure that this requirement ismet if portable air compressor is being used to supply breathing air.The use of filters on any air intake should be of secondary importance whencompared with the foregoing requirements.
1.6 GENERAL WORKS AIR SUPPLY SYSTEMSWhere the air supply is used in the manufacturing process as well as in thesupply of respirable air, particular care should be taken to avoid the risk ofcontamination.
Where the air supply is used in the manufacturing process and there is a risk ofcontamination, the air supply should not be used for personal protection unless ithas been filtered to provide the air quality defined in paragraph 1.
In every instance it should be ensured that any back pressures from operatingplants using the air supply will not cause contamination of the air used forpersonal protection.
Provision should be made to ensure that the air lines supplying the breathingapparatus receive a adequate supply of respirable air under all plant operatingconditions.
Plant air supplies are not suitable for air-line respirators unless special
precautions have been taken for the elimination of scale, rust, water, oil mist,irritating ingredients and odours. It is preferable that a separate installation beprovided for respiratory air purposes, and that it be designed to eliminate theabove mentioned contaminants.
50 SAFE USE OF ISOCYANATES
2. COMPRESSED OXYGEN SUPPLY
Compressed oxygen of the dry breathing type should he odourless and containnot less than 99.5 percent by volume of oxygen.At 15°C and 100 kPa absolute, it should contain:
(a)less than 11 mg/m3 (10 p.p.m. by volume) of carbon monoxide; and(b)less than 1400 mg/m3 (800 p.p.m. by volume) of carbon dioxide.
SAFE USE OF ISOCYANATES 51
APPENDIX 7: MEASUREMENT OF AIRMOVEMENT IN FULL DOWN-DRAUGHTBOOTHS
52 SAFE USE OF ISOCYANATES
The procedure to be used for determining the air movement shall be:
1.Divide the booth up into a grid of 9 equal areas.
2.
With the booth empty, measure the average downward air velocity0.5m below the ceiling filter at the centre of each grid, using a hotwire anemometer. Avoid taking measurements immediately below thefilter support frame.
3.No single measurement shall be less than 0.10 m/sec.
4.
It is recommended that the average of the 9 grid measurements
should be 0.23 m/sec or more. In no circumstances shall the minimumaverage air movement be less than 0.20 m/sec.
APPENDIX 8: GUIDANCE NOTE ONRECOMMENDED CONSTRUCTIONMATERIALS FOR SPRAY BOOTHS
The construction of any spray booth may be varied from the requirements ofthe Spray Coating Regulations 1962, provided that any alternative constructionor lining materials are not ignitable when tested for flammability by AS: 1530Pt3: 1989. In addition, the smoke index obtained shall not exceed 5, and thelinings must have smooth, easily cleaned surfaces.
SAFE USE OF ISOCYANATES 53
APPENDIX 9: RELATED LEGISLATION
Health and Safety in Employment Act 1992 and Regulations — Providebasic occupational safety, health and welfare requirements in factories andundertakings. These include in plant environmental controls to cover such itemsas ventilation, atmospheric conditions, lighting, noise, and preventative measuresfor dust explosions.
Other matters covered include protective clothing and equipment, storage ofmaterials, access and egress, provision of amenities such as meal rooms, toilets,and machine guarding.
Factories and Commercial Premises Act (First Aid) Regulations 1985— Prescribe certain requirements for the provision of first aid kits and theircontents, the appointment of persons to administer first aid and the provision offirst aid rooms in undertakings employing 100 or more staff.
Spray Coating Regulations 1962 — Require the provision of spray boothsand cabinets where spray coating is performed. The regulations specify theconstruction requirements of spray booths and rooms and also specify
ventilation requirements including the discharge of fumes. Requirements fordrying ovens, electrostatic spray coating and storage of flammable substancesare also included.
Toxic Substances Regulations 1983 — These regulations specify thelabelling requirements for containers of TDI and HDI. They are administeredby the Public Health Unit at the local Crown Health Enterprise.
Resource Management Act 1991 — Commercial users of isocyanates maybe required, under section 15, to obtain a resource consent (discharge permit)for emissions to air, water or land. Users should contact their regional counciloffice for further information (see section 9.4).
Building Act 1991 — Regional council authorities administer the Building Actand other legislative requirements covering items such as building construction,waste disposal, siting of industries, storage of dangerous goods and fireprecautions.
RELATED STANDARDSNZS/AS 1715: 1991. Selection, use and maintenance of respiratory devices.NZS/AS: 1991. Respiratory protective devices.
RELATED BOOKLETS AVAILABLE FROM OSHA Guide to Respirators and Breathing Apparatus.Guide to the Spray Coating Regulations.Welding Safety.
How to use Isocyanates Safely (A bulletin for spray painters).
54 SAFE USE OF ISOCYANATES
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