TWAC Protectant, Installation Manual

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TWAC Installation Manual Ver: 0118 CodeMark™ CMA-CM40036
3.3 Workplace Exposure
Chemicals are often allocated an exposure level or standard. In Australia, these exposure levels can
be found on the National Hazardous Substances Information System (HSIS). Exposure levels for
any of the ingredients found in any of the Protectant™ Termite Barrier System Components are
recorded on the appropriate Material Safety Data Sheets. Exposure standards represent airborne
concentrations of individual chemical substances, which according to current knowledge, should
neither impair the health nor cause undue discomfort to nearly all workers.
Normally, exposure standards apply to long-term exposure to a substance over an eight-hour day,
for a five-day working week, over an entire working life. This is known as the time-weighted
average (TWA). Exposure standards do not guarantee protection to every worker. Because of
biological variation and the range of individual susceptibilities to certain chemicals, a small
proportion of people may suffer mild discomfort at or near the standard. Rarely a person may
become ill.
The exposure standards are not a fine dividing line where exposure just below or at the standard is
acceptable. They are an indicator as to whether workplace controls are sufficient to provide a
suitable working environment.
3.3.1 Exposure Excursions
As stated, the exposure standards are based upon eight-hour days, five-days per week, over a
working lifetime. This means that sometimes people may be exposed to levels above the standard
for short periods of time and the low levels compensate for this at different times during the day.
However it is an unacceptable practice to expose staff to levels significantly above the standard.
Consideration must be given to the acute effects of short-term exposure or to the relationship
between accumulation and elimination from the body of the material or its metabolites when the
body breaks the material down.
Some materials may affect workers after only brief overexposure, although the primary toxic effects
may be due to long-term exposure via accumulation or gradual health reduction with repeated
exposure. For this reason, some chemicals have a short term exposure limit (STEL) assigned to
them. STELs are only recommended for materials where there is evidence that adverse effects can
be caused by high, short-term exposure.
STELs are expressed as airborne concentrations averaged over 15 minutes. The STEL should not
be exceeded at any time during a normal 8-hour day. Staff should not be exposed to the STEL
concentration continuously for periods exceeding 15 minutes, or for more than four such periods in
the working day. A minimum of one hour should be allowed between successive exposures at the
STEL value. Again, materials in any of the Protectant™ Termite Barrier System components that
have an associated STEL value will have it recorded in the Material Safety Data Sheet.
4.0 Chemicals
There are a variety of chemicals used in the workplace. Chemicals can occur in all three physical
states, i.e. solids, liquids and gases. The manufacture, importation, transportation, storage and
usage of chemicals are covered by a variety of legislation. In respect to usage in the workplace, we
are more concerned with those chemicals that are classified as either Hazardous Substances or
Dangerous Goods.
Approximate definitions for our purposes are:

Hazardous substances are chemicals or substances that are deemed to be harmful to your
health . In legislative terms, a substance is defined as Hazardous if it is listed on the National
Hazardous Substances Information System (HSIS) and the concentration of the substance or
its ingredients equals or exceeds the listed concentration cut-off levels, or it meets the criteria
as specified in the Approved Criteria for Classifying Hazardous Substances.