ISRP 2002 abstract
| Presenter/author | Title | Abstract |
|
Berndtsson, Goran The SEA Group, Branford, Connecticut, USA |
The Role of Peak Inhalation Air Flow in the Testing of Air Purifying Respirators |
It has been well known since the 1940s that
humans are capable of breathing much more air, and at much faster flows,
than the airflow used in the testing of filters. This is confirmed by a
great number of tests on real people at normal work, yielding a large
collection of detailed data. One test involved 90 minutes’ continuous
logging of the breathing cycle of workers performing normal work
routines. Another test measured the breathing of fire fighters climbing
the stairs of a high-rise building. The test equipment measured the
volume and speed of every breath, minute volume, and total volume of air
breathed during the entire period. These tests show that on average,
60–70% of the air breathed by a person performing moderate work is above
the flow rate at which filters are commonly tested (95 l/min). In terms
of PIAF, about 40% of a working person’s flow rate is more than twice
the test rate, and about 10–15% is more than 3 times the test flow.
This paper presents the data and discusses the implications of the findings; among other things, that filters need to be tested at higher, more representative flow rates, and at more than one rate.
|