HAZWOPER PPE Ensembles Considerations
Work Mission Duration
A routine should be established and practiced periodically for donning a fully-encapsulating suit/Self Contained Breathing Apparatus (SCBA) ensemble. Assistance should be provided for donning and doffing since these operations are difficult to perform alone, and solo efforts may increase the possibility of suit damage. Once the equipment has been donned, its fit should be evaluated. If the clothing is too small, it will restrict movement, thereby increasing the likelihood of tearing the suit material and accelerating worker fatigue. If the clothing is too large, the possibility of snagging the material is increased, and the dexterity and coordination of the worker may be compromised. In either case, the worker should be recalled and better fitting clothing provided. Before HAZWOPER workers actually begin work in their PPE ensembles, the anticipated duration of the work mission should be established. Several factors limit mission length.
• Air supply consumption.
• Suit/ensemble permeation and penetration by chemical contaminants.
• Ambient temperature.
• Coolant supply.
Air Supply Consumption
The duration of the air supply must be considered before planning any SCBA assisted work activity. The anticipated operating time of an SCBA is clearly indicated on the breathing apparatus. This designated operating time is based on a moderate work rate, e.g., some lifting, carrying, and/or heavy equipment operation. In actual operation, however, several factors can reduce the rated operating time when planning an SCBA-assisted work mission, the following variables should be considered and work actions and operating time adjusted accordingly:
• Work rate. The actual in-use duration of SCBAs may be reduced by one-third to one-half during strenuous work, e.g., drum handling, major lifting, or any task requiring repetitive speed of motion.
• Fitness. Well-conditioned individuals generally utilize oxygen more efficiently and can extract more oxygen from a given volume of air (particularly when performing strenuous tasks) than unfit individuals, thereby slightly increasing the SCBA operating time.
• Body size. Larger individuals generally consume air at a higher rate than smaller individuals, thereby decreasing the SCBA operating time.
• Breathing patterns. Quick, shallow or irregular breaths use air more rapidly than deep, regularly spaced breaths. Heat-induced anxiety and lack of acclimatization (see Heat Stress and Other Physiological Factors in our HAZWOPER training) may induce hyperventilation, resulting in decreased SCBA operating time.
Suit/Ensemble Permeation and Penetration
The possibility of chemical permeation or penetration of Chemically Protective Clothing (CPC) ensembles during the work mission is always a matter of concern and may limit mission duration. Possible causes of ensemble penetration are:
• Suit valve leakage, particularly under excessively hot or cold temperatures.
• Suit fastener leakage if the suit is not properly maintained or if the fasteners become brittle at cold temperatures.
• Exhalation valve leakage at excessively hot or cold temperatures. Also, when considering mission duration, it should be remembered that no single clothing material is an effective barrier to all chemicals or all combinations of chemicals, and no material is an effective barrier to prolonged chemical exposure.
The ambient temperature has a major influence on work mission duration as it affects both the worker and the protective integrity of the ensemble. Heat stress, which can occur even in relatively moderate temperatures, is the greatest immediate danger to an ensemble-encapsulated worker. Methods to monitor for and prevent heat stress are discussed in our training.
Hot and cold ambient temperatures also affect:
• Valve operation on suits and/or respirators.
• The durability and flexibility of suit materials.
• The integrity of suit fasteners.
• The breakthrough time and permeation rates of chemicals.
• The concentration of airborne contaminants. All these factors may decrease the duration of protection provided by a given piece of clothing or respiratory equipment.
Under warm or strenuous work conditions, adequate coolant (ice or chilled air) should be provided to keep the wearer's body at a comfortable temperature and to reduce the potential for heat stress. If coolant is necessary, the duration of the coolant supply will directly affect mission duration.
Personal Use Factors
As described below, certain personal features of workers may jeopardize safety during equipment use Prohibitive or precautionary measures should be taken as necessary. Facial hair and long hair interfere with respirator fit and wearer vision. Any facial hair that passes between the face and the sealing surface of the respirator should be prohibited. Even a few days' growth of facial hair will allow excessive contaminant penetration. Long hair must be effectively contained within protective hair coverings. Eyeglasses with conventional temple pieces (earpiece bars) will interfere with the respirator-to-face seal of a full facepiece. A spectacle kit should be installed in the face masks of workers requiring vision correction. When a worker must wear corrective lenses as part of the facepiece, the lenses shall be fitted by qualified individuals to provide good vision, comfort, and a gastight seal. Contact lenses may trap contaminants and/or particulates between the lens and the eye, causing irritation, damage, absorption, and an urge to remove the respirator. Wearing contact lenses with a respirator in a contaminated atmosphere is prohibited (29 CFR Part 1910.134[e][ii]). Gum and tobacco chewing should be prohibited during respirator use since they may cause ingestion of contaminants and may compromise the respirator fit.