Air and noise
Guidelines
Spray coating activities–control of air and noise emissions
Updated August 2012
EPA 100/12: This guideline replaces an earlier version (Spray painting activities–control of air and noise emissions, May
2011). It provides information to persons undertaking spray coating activities to assist in minimising air and noise
impacts.
Introduction
Environmental pollution from a spray coating operations is controlled by the Environment Protection Authority (EPA).
Occupational aspects, such as ventilation of the work area and worker noise exposure, are the responsibility of SafeWork
SA.
Environment Protection Act 1993
The principal legislation dealing with pollution in South Australia is the Environment Protection Act 1993 (the EP Act). In
particular, section 25 imposes a general environmental duty on all persons undertaking an activity that may pollute to
take all reasonable and practicable measures to prevent or minimise any resulting environmental harm.
‘Surface coating’, which includes spray coating operations (specifically spray painting and powder coating), is listed in
Schedule 1 of the Act as a prescribed activity of environmental significance. This means that any spray coating operation
with a capacity to use more than 100 litres of paint per day, or 10 kg of dry powder per day, is required to be licensed
under the Act.
Environment protection legislation also includes environment protection policies (EPP), which may outline both
recommendations and mandatory requirements for the protection of a particular aspect of the environment, such as air
quality.
Environment Protection (Air Quality) Policy 1994
Air pollution is primarily governed through the Environment Protection (Air Quality) Policy 1994 (Air Policy). The Air Policy
specifies maximum allowable pollution levels from point sources and requires that the best practicable means of control
be used to minimise air pollution of any kind.
Premises at which spray coating takes place may be required under the Air Policy to take all reasonable and practicable
measures deemed necessary to reduce air pollution, either by a condition of an EPA licence, or by an environment
protection order (EPO).
Environment Protection Authority
Spray coating booths—control of air and noise emissions
Environment Protection (Noise) Policy 2007
The Environment Protection (Noise) Policy 2007 (Noise Policy) provides guidance on noise levels that may be
considered excessive under the EP Act. It should be noted that the Act requires site-specific issues be taken into account
when determining noise levels that may be excessive.
It is important to ensure that all practicable steps are taken to minimise the adverse effect that noise emissions may have
on the amenity value of an area. This includes not only noise emitted from the coating equipment itself but also noise
from other sources, such as radios, extraction fans and air compressors.
The EPA may issue an EPO requiring that excessive noise be reduced to acceptable levels within a specified period.
Common sources and controls of air and noise emissions
The following information aims to assist the operator in minimising the environmental impacts of coating activities.
Intermittent, light or electrostatic coating
When coating applications are light or intermittent, or the overspray is to be reduced by using an electrostatic method, it
is acceptable that the exhausted air is filtered using a dry disposable filter. The following points should, however, be
taken into consideration:

The dry filter should be suitable for collecting the spray coating. Certain spray coatings, such as lacquers and fastdrying enamels, may be difficult to trap. Advice on the effect of spray coatings on the filter should be sought from the
suppliers of both the spray coating and the disposable filters.

The efficiency of a dry filter spray booth is related to the filter’s cleanliness. A manometer or pressure gauge should
be fitted to the spray booth’s filter unit, and the filter changed when the manometer reading reaches the level
specified by the manufacturer.

The air movement through the filter should correspond with the manufacturer’s recommendations for maximum
filtration efficiency.
Regular spray coating
When a process requires large quantities of coating to be sprayed on a regular basis, a spray booth incorporating an
efficient wet collection device is normally required. An efficient wet collector uses a spray chamber containing sufficient
spray nozzles with adequate water circulation to remove coating particles.
An alternative to the spray chamber is the so-called ‘no-pump’ collection device, in which water is combined with the paint
particles by air movement. To obtain maximum filtration efficiency with this type of collector it is important to maintain the
correct water level, as recommended by the manufacturer. An automatic water level control device should be fitted to all
spray booths of the no-pump type. If the level controller incorporates an electrically operated switch or valve, the device
should be electrically interlocked with the ventilation fan. This will ensure that the fan operates whenever the booth is
used.
A water curtain is useful only to maintain booth cleanliness and is not acceptable to the EPA as a collection device. A
separate wet collector should be incorporated in the unit along with the curtain.
The efficiency of any spray booth is related to its cleanliness. Authorised officers may inspect the filter equipment in spray
booths to check whether it is adequately maintained.
Use of non-aqueous solvent-based coatings
When non-aqueous solvent-based coatings are used (such as acrylic and isocyanate paints), section 25 of the EP Act
requires that everything reasonable and practicable is done to ensure that solvents evaporated during the coating and
drying process are appropriately managed to avoid potential air pollution impacts upon neighbouring land uses.
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Spray coating booths—control of air and noise emissions
Managing solvent emissions by dispersion
For most smaller operations, solvent emissions from spray coating can be adequately managed by good fume collection
and atmospheric dispersion via engineered stacks.
The EPA Guideline Air quality impact assessment using design ground level pollutant concentrations (DGLCs) specifies
maximum ground level concentrations permitted for polluting compounds commonly found in solvent-based coatings
(eg xylenes, toluene, ethyl acetate, etc).
To apply the guideline, a proponent should first determine how much solvent will be emitted. This can be done using
composition data in the material safety data sheet (MSDS) that should be provided by the coating supplier. If coating use
is not uniform, only the period of greatest use should be considered; if coatings of different compositions are used at
different times, individual estimates of solvent emission should be made for the different coatings.
The airflow in the exhaust system should then be determined from either the system supplier or by actual measurement.
The exhaust system may include spray booth and building exhaust.
The concentration of individual pollutants in the exhaust air can now be calculated by dividing the mass of each solvent
emitted by the total exhaust airflow volume. Sample calculations can be found at the end of this guideline in
Attachment 1 and will assist in determining whether the ‘simplified approach’ (outlined below) is applicable.
Simplified approach for relatively small emission rates
In some situations, the concentration of a pollutants arising from spray coating activities may be sufficiently small that the
EPA, based on its experience, would be satisfied that DGLCs would be met without the need for verification through
pollutant dispersion modelling.
In general, the need for pollutant dispersion modelling may be waived at the discretion of the EPA if it can be shown that:

the emission is released from a single point source and contains a concentration of any pollutant of not more than
100 times the DGLC of the pollutant, when measured at the top of the stack (refer to Attachment 1 for sample
calculations and determinations)

the emission will be discharged from a stack which discharges to atmosphere at least three metres above the highest
point within a 30-metre radius of the stack

the emission has a discharge velocity no less than 10 metres per second

the stack does not have a conical or similar rain protector that interferes with the upward exit flow.

the proposed facility exists within flat terrain with no unusual meteorological factors. Note: a flat cut made into
the side of a hill is not considered ‘flat terrain’.
If the simplified approach is not applicable, computer dispersion modelling should be considered to design an extraction
system including stacks) that adequately disperses the pollutants.
Managing larger solvent emissions
Where the solvent emission is sufficiently large to make dispersion impracticable, a solvent destruction process should be
employed. The most common technology used for this purpose involves thermal oxidation. The proponent will need to
select the technology most appropriate to the particular circumstances.
Managing fugitive solvent emissions
The proponent should consider how fugitive solvent emissions will be managed. The most common sources of fugitive
solvent emissions are doors and windows that are opened to provide cooling for non-airconditioned buildings.
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Spray coating booths—control of air and noise emissions
Where this practice occurs, the building should be adequately ventilated (ie sufficient negative pressure maintained) to
ensure solvent fume escape is minimised through these openings.
Managing coating systems that evolve gaseous reaction products
Where coating systems form gaseous reaction products such as formaldehyde during drying and/or curing, the mass of
reaction products formed should be determined by either discussion with the coating supplier or by measurement.
An approach similar to that used for managing solvent emissions can then be used.
An example of such a calculation (Example 3) is given in Attachment 1.
Managing coating systems containing isocyanates
Where coating systems (such as polyurethane) contain isocyanates (MDI, TDI, etc) the proponent should demonstrate (in
addition to adequate dispersion of any solvents and reaction products) that any overspray which results from coating is
adequately collected and not allowed to escape to the atmosphere.
Noise from spray booths
Some spray booth equipment (including extraction fans) may cause excessive noise at neighbouring properties. When a
spray booth is being installed it is essential that the maximum noise emission level of the extraction fans and any other
equipment be considered, especially when it is to be operated near residences or neighbouring workplaces.
Usually the manufacturer will be able to advise on the noise emission level of the spray booth. If not, testing should be
carried out. The manufacturer or installer should then advise on the suitability of the equipment for a given location. For
example, the closer a unit is to a neighbour, the quieter it should be. Ideally, a guarantee that the operation of the spray
booth will not contravene the Noise Policy should be obtained.
Finally, it is good practice to check that the spray booth complies with the night time maximum permissible noise level,
even if the unit is not intended to be used at night. Circumstances may change, especially in a developing industry,
requiring occasional or even regular operation at night. It is always cheaper to design for lower noise levels when
purchasing or siting equipment than to reduce noise from existing sources.
Separation distances
Conflict with residents will generally be avoided if a distance of at least 50 metres is maintained between spray booth
stack outlets and the nearest residential boundary. If a distance of 50 metres cannot be achieved, a higher exhaust duct
may be acceptable (pending council approval) as a means of protecting local amenity. However, advice should be sought
from the EPA, including reference to the EPA Guideline Odour assessment using odour source modelling.
Self-audits
An environmental audit should be conducted every year to ensure that spray coating activities are undertaken in
accordance with environmental objectives and within legislative requirements.
Setting up environmental complaint procedures, and training staff to recognise and minimise environmental hazards are
also good ways of ensuring acceptable plant performance.
Disclaimer
This publication is a guide only and does not necessarily provide adequate information for every situation. This
publication seeks to explain your possible obligations in a helpful and accessible way. In doing so, however, some detail
may not be captured. It is important, therefore, that you seek information from the EPA itself regarding your possible
obligations and, where appropriate, that you seek your own legal advice.
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Spray coating booths—control of air and noise emissions
Further information
Legislation
Legislation may be viewed on the Internet at: <www.legislation.sa.gov.au>
Copies of legislation are available for purchase from:
Service SA Government Legislation Outlet
Adelaide Service SA Centre
108 North Terrace
Adelaide SA 5000
Telephone:
Facsimile:
Website:
13 23 24
(08) 8204 1909
<shop.service.sa.gov.au>
Telephone:
Facsimile:
Freecall (country):
Website:
Email:
(08) 8204 2004
(08) 8124 4670
1800 623 445
<www.epa.sa.gov.au>
<epainfo@epa.sa.gov.au>
For general information please contact:
Environment Protection Authority
GPO Box 2607
Adelaide SA 5001
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Spray coating booths–control of air and noise emissions
Attachment 1
Sample desktop calculations–DGLCs and pollutant
dispersion modelling
Example 1
Exhaust air flow through booth
6,000 cubic metres per hour
Paint application rate
2 litres per hour
Maximum pollutant content of coating (from MSDS)
Benzene
Toluene
Xylenes
7.5% v/v
20% v/v
25% v/v
Benzene
Toluene
Xylenes
0.2 litres per hour
0.4 litres per hour
0.5 litres per hour
Maximum evaporation rate of pollutants
Mass evaporation rates assuming Specific Gravity (SG) =0.85
Benzene
Toluene
Xylenes
128 grams per hour
340 grams per hour
425 grams per hour
Concentration of pollutants in booth exhaust
Benzene
Toluene
Xylenes
21 mg per cubic metre
57 mg per cubic metre
71 mg per cubic metre
Maximum concentration of pollutants allowable for the simplified approach to apply (100 times DGLC)
Benzene
Toluene
Xylenes
5 mg per cubic metre
65 mg per cubic metre
35 mg per cubic metre
Result: benzene and xylene concentrations in booth exhaust exceed limit for simplified approach (ie greater than
100 times DGLC) so modelling would be recommended to demonstrate adequate dispersion.
Example 2
Exhaust air flow through booth
10,000 cubic metres per hour
Paint application rate
2 litres per hour
Maximum pollutant content of coating (from MSDS)
Benzene
Toluene
Xylenes
2.5% v/v
30% v/v
20% v/v
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Spray coating booths–control of air and noise emissions
Maximum evaporation rate of pollutants
Benzene
Toluene
Xylenes
0.1 litres per hour
0.6 litres per hour
0.4 litres per hour
Mass evaporation rates assuming SG=0.85
Benzene
Toluene
Xylenes
43 grams per hour
510 grams per hour
340 grams per hour
Concentration of pollutants in booth exhaust
Benzene
Toluene
Xylenes
4 mg per cubic metre
51 mg per cubic metre
34 mg per cubic metre
Maximum concentration of pollutants allowable for the simplified approach to apply (100 times DGLC)
Benzene
Toluene
Xylenes
5 mg per cubic metre
65 mg per cubic metre
35 mg per cubic metre
Result: benzene, toluene and xylene concentrations in booth exhaust are all below limit for simplified approach
so modelling would not be required in this case.
Example 3
Exhaust air flow through booth
10,000 cubic metres per hour
Coating application rate
2 litres per hour
Curing evolves 5 grams of formaldehyde per litre of coating
Maximum emission rate of pollutants
10 grams per hour
Concentration of pollutants in booth exhaust
1 mg per cubic metre
Maximum concentration of pollutants allowable for the simplified approach to apply (100 times DGLC)
Formaldehyde
4 mg per cubic metre
Result: formaldehyde concentration in booth exhaust is below limit for simplified approach, so modelling would
not be required in this case.
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