Workers wearing a respirator carry out a given task 20 to 25 % more slowly than they would without a respirator. In an area where external radiation and air contamination are present, the decision should comply with the ALARA principle to minimize the sum of the external and internal dose. Working with breathing equipment increases the load on the heart and lungs. For this reason all workers who are likely to use respirators must undergo a special additional medical examination. Respiratory equipment falls into three main groups (Table 7.6): air-purifying respirators (air filtration), air-line respirators (with air supplied via a hose), self-contained breathing apparatus. Table 7.6: Characteristics of respiratory equipment. PF PF type shape principle of operation particles particles only and gases half facepiece negative pressure during 10 inhalation full facepiece negative pressure 50 during inhalation filtration full facepiece positive pressure 1000 air half facepiece continuous air flow 1000 half facepiece flow during inhalation 10 full facepiece continuous air flow 2000 full facepiece flow during inhalation 50 full facepiece positive pressure, flow air-line 2000 during inhalation suit continuous air flow 2000 full facepiece flow during inhalation 50 full facepiece positive pressure, flow during inhalation full facepiece closed-circuit breathing 50 breathing apparatus full facepiece closed-circuit breathing, 5000 self-contained positive pressure The first group includes e.g. a filter half mask (Figure 7.3), the second an air-line suit (Figure 7.4) and the third a mask with air supplied from a cylinder (Figure 7.5). Figure 7.3: Filter half mask.
Workers wearing a respirator carry out a given task 20 to 25 % more slowly than they would without a respirator. In an area where external radiation and air contamination are present, the decision should comply with the ALARA principle to minimize the sum of the external and internal dose. Working with breathing equipment increases the load on the heart and lungs. For this reason all workers who are likely to use respirators must undergo a special additional medical examination. Respiratory equipment falls into three main groups (Table 7.6): air-purifying respirators (air filtration), air-line respirators (with air supplied via a hose), self-contained breathing apparatus. Table 7.6: Characteristics of respiratory equipment. type shape principle of operation PF particles only PF particles and gases air filtration half facepiece negative pressure during inhalation 10 full facepiece negative pressure during inhalation 50 full facepiece positive pressure 1000 air-line half facepiece continuous air flow 1000 half facepiece flow during inhalation 10 full facepiece continuous air flow 2000 full facepiece flow during inhalation 50 full facepiece positive pressure, flow during inhalation 2000 suit continuous air flow 2000 self-contained breathing apparatus full facepiece flow during inhalation 50 full facepiece positive pressure, flow during inhalation full facepiece closed-circuit breathing 50 full facepiece closed-circuit breathing, positive pressure 5000 The first group includes e.g. a filter half mask (Figure 7.3), the second an air-line suit (Figure 7.4) and the third a mask with air supplied from a cylinder (Figure 7.5). Figure 7.3: Filter half mask.