Page 22 - PPE GUIDELINE

Guidelines on the Use of PPE Against Chemical Hazards

Example of Using the Assigned Protection Factor Table and the Selection Flowchart.

Let assume the following scenario:
Chemical used : Acetone
Permissible Exposure Limit (PEL) : 500 ppm
Immediately Dangerous to Life and Health (IDLH) : 20000 ppm
Exposure level (at work area) : 1788 ppm
Oxygen deficiency potential : No

Calculate the Hazard Ratio:

Hazard Ratio = Exposure Level ÷ PEL
= 1788 / 500
= 3.6

Because this is a not an oxygen deficiency environment with a hazard ratio of more
than 1X PEL but less than 10X PEL, therefore, the recommended respirator is an air-
purifying half face-piece respirator.

Note: APF and the Selection Chart help to determine the right type of respirator for
air-purifying respirator. It does not tell us which type of filtration media to be
used.

Since the Assigned Protection Factor and Selection Chart will not tell us which type
of filtration media to be used a guide is necessary. Table 4 is the guide to help you
selecting the filter media for certain chemicals, based on NIOSH (USA) standard.

It is important to note that not all gases and vapours can be absorbed effectively with
the use of chemical cartridges. Good examples are those chemical that has no smell
(e.g. carbon monoxide) or have a very short service life on the cartridge (e.g.
methanol).

Selecting the suitable respirator is very critical in preventing worker’s exposures to
chemical hazardous to health. It is very important to ensure that only the correct type
of respirator and filter media is being used, and where there is any doubt, expert
and/or manufacturer’s advice should be sought.

Department of Occupational Safety & Health, Ministry of Human Resources, Malaysia ™October 2005 22