(A) Choosing the correct equipment involves several steps:
(1) Identifying the hazard and its extent;
(2) Choosing equipment that is certified/approved for the function; and
(3) Assuring that the device is performing the function it is intended to perform.
(B) In identifying the hazard it is necessary to assess the work environment by determining the nature and extent of the hazard, work rate, area to be covered, existing space and ventilation, mobility, work requirements and conditions, as well as the limitations and characteristics of the available respirators are selection factors. If a specific standard exists for the hazard (e.g. lead, asbestos), the guidelines or requirements in the standard must be followed. Also the chemical and physical properties of a harmful, irritating, or nuisance airborne material as well as the published Threshold Limit Values (TLV), Permissible Exposure Limits (PEL), or any other available exposure limits or estimates of toxicity for the materials and the amount of oxygen present must be considered.
(C) Although there are many kinds of respirators used for protection, there are two basic types—air-purifying and atmosphere-supplying respirators.
(1) Air-purifying respirators use filters or absorbents to remove limited concentrations of contaminants from the breathing air. They range from simple disposable masks to half- and full-face respirators to sophisticated positive pressure, blower-operated units. Air purifying respirators may not be used in an oxygen deficient atmosphere or under immediately dangerous to life or health (IDLH) conditions. OSHA defines an IDLH atmosphere as any atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere.
(2) Atmosphere-supplying respirators are designed to provide breathing air from a clean source outside of the contaminated work area. They include supplied air respirators (SAR) and self contained breathing apparatus (SCBA).
(D) The time needed to perform a given task usually determines the length of time for which respiratory protection is needed, including the time necessary to enter and leave a contaminated area. An SCBA or chemical cartridge respirator provides respiratory protection for relatively short periods, whereas an airline respirator provides protection for as long as the face piece is supplied with an adequate quantity of respirable air. For protracted periods of use, positive pressure supplied air respirators offer the advantage of longer use in highly contaminated areas and minimize the need for concern regarding sensory warning properties of the airborne toxic materials. Positive pressure supplied air respirators also cause less discomfort than air-purifying respirators because the wearer need not overcome filter resistance in order to inhale.
(E) Some type of service life warning indicator is available for all SCBA and some chemical cartridge respirators. The warnings usually are an audible alarm based on remaining pressure for SCBA and a color-change indicator for cartridges. The user must understand the operation and limitations of each type of warning device and of each type of respirator. Air-purifying respirators present minimal interference with the wearer's movement while SCBA present size and weight (35 lbs) penalties.
(F) Three types of respirators generally are available at the city for general and type-specific uses. The Director of Administrative Services must be contacted concerning the selection or use of any type of respirator.
(1) Negative pressure respirators. The air pressure inside the respiratory inlet covering is negative with respect to ambient air during inhalation. Negative Pressure Regulators are the dust filter masks used by buildings and grounds personnel while cutting grass etc.
(2) Positive pressure respirators. The air pressure inside the respiratory inlet covering normally is positive with respect to ambient air pressure. These are the SCBA utilized by the city for emergency response operations involving unknown or suspected IDLH hazards or confined space entry/rescue.
(3) Air-purifying respirators. Inhaled air is drawn through a canister/cartridge which contains chemicals and a filter that removes or neutralizes agents present. These units are used by the city for task specific non-IDLH conditions.
(G) The decision to use negative pressure, positive pressure, or air-purifying respirators will be based on whether or not the work involved will be considered IDLH, has specific respirators designated, or is of a routine nature with published TLV's, PEL's, etc. which can be used to determine the appropriate protection factor (PF).
(H) The Director of Administrative Services will provide assistance in determining the correct type respirator for routine use. This assistance will include working with the appropriate Safety Department Chairperson/Training Officer to evaluate the respiratory hazards in the particular workplace with regard to selecting the general type of respirator required to assure worker safety under the OSHA standard.
(I) All emergency situations will be handled as IDLH unless the exact type and, if possible, concentration of the substance is known. Any IDLH entry requires one standby person in a safe area with SCBA for each person working in the entry or clean-up phases of the emergency operation.
(Ord. 38-2005, passed 10-11-05)