Introducing
FitTester 3000, a revolutionary new system that's been accepted by
OSHA for use in all types of quantitative fit test programs. With a patented fit
testing technique known as controlled negative pressure, FitTester 3000 offers
test results that are more reliable than those obtained
with any other method currently available, including
qualitative methods and particle counting devices. You'll also appreciate
easy-to-conduct tests, speedy fit factor calculations, preprogrammed exercise
and test protocols that meet OSHA requirements, and a price that's extremely
competitive.
The
FitTester 3000 ready to fit test a respirator.
While
the concept is simple, no other fit test system can offer the precision and
accuracy offered by FitTester 3000. In fact, comparison studies have shown that
the controlled negative pressure (CNP) technique provides a more accurate
measure of respirator fit than aerosol-based devices. The CNP system is the only
fit test technology on the market to offer overwhelming scientific proof of such
accuracy. The FitTester 3000's accuracy is calibrated to a traceable NIST
standard. Competitive products cannot measure up to the accuracy provided by the
FitTester 3000 PERIOD!
CNP
technology is different
because it allows you to take a direct volumetric measurement of leakage into
the mask. To do so, the respirator inlets are capped with test adapters, and the
inhalation valves are propped open or removed. With the test subject holding his
or her breath for about 10 seconds, FitTester 3000 then establishes and
maintains a slight vacuum, or controlled negative pressure, inside the mask.
Since the respirator inlets are sealed, all sources of leakage into the
mask are checked. The volume of air drawn out of the mask during the CNP
measurement equals the leakage of air into the mask. It’s that easy.
To
help you better understand the advantages of using CNP technology, let's take a
look at the shortcomings of the most-used quantitative fit test method, particle
counting. To determine respirator fit, a particle-counting device alternately
samples the aerosol concentration both inside a mask and in the ambient air
surrounding the mask. The particles in these samples are then coated with
alcohol to make them detectable by a light beam counting device.
The particle-counting device estimates a fit factor by dividing the average
count from an approximate 40 second in-mask sample by the average count from an
approximate 10-second ambient air sample. Let’s look at some of the reasons
aerosol measurements tend to misread respirator fit.
If
the ambient air particulate concentration is too low (requiring burning incense
or candles), there may be problems with count statistics. Ambient air
particulate concentrations that are too high could result in dirty optics that
lead to miscounted particles. There are other documented problems with particle
counting as well, called sampling biases.
A
particle counting device cannot detect respirator leakage unless its challenge
agent (ambient aerosol particles) can reach its detector. If an ambient particle
leaks into the respirator but has no chance to physically migrating to the
detector. An error or bias is introduced into the measurement. Documented
sources of aerosol system measurement bias include but are not limited to leak
site penetration losses, streamlining, and lung deposition.
First,
the variety of sizes and shapes of respirator face seal leaks can strongly
influence the ability of an ambient air particle to leak into the mask (see
Figure 1). Just because a particle can’t penetrate a leak site, we cannot be
certain that a gas or vapor molecule could not penetrate the same leak site. At
present, we can only assume that aerosol-based fit tests provide good estimates
for gas or vapor contaminants.
Figure 1
There
is also the case of particle streamlining (see Figure 3). During inspiration,
the ONLY time contaminants leak into the respirator, the lungs take in air at a
flow rate of 50,000 ml/min or MORE, depending on work rate Aerosol-based
quantitative systems typically sample at rates of only 700 ml/min.
Figure 3
Which
direction, lungs or sampling probe, do you think a particle is more likely to
go? This streamlining phenomenon causes poor in-masking mixing and prevents a
large number of particles from reaching the aerosol-sampling probe. If the
particle doesn’t reach the probe, the aerosol-based fit test device remains
oblivious to the leak. In essence, a system that can’t see a particle can’t
count it either.
Particles
that enter a respirator through a leak site have a very high probability of
being carried by inspired air into the respiratory system. Once there, a
significant number (50% or greater) of those particles may become deposited on
lung surfaces and are no longer present in the exhaled air stream, when a
particle counting device would have its best chance of detecting them. As a
result, such devices have a big tendency to under-estimate respirator leakage
and over-estimate fit, since you may be exhaling cleaner air than you inhale.
Take a moment to think about the incredibly high fit factors routinely reported
by aerosol-based quantitative fit test systems, and the validity of the
preceding statement becomes obvious.
Since the particle counting sampling biases mean elevated fit factors with a significant margin of error. That could make the difference between a respirator that is protecting an employee's health and one that is not. FitTester 3000's advanced CNP technology uses pressure wave propagation instead of particle migration to measure mask leaks, so there are no aerosol particles to worry about losing before they can physically migrate to the sampling probe and particle detector. lnstead, CNP technology gives you get a direct measurement of respirator leakage quickly and accurately regardless of the source. The sampling biases related to aerosol concentration, lung deposition, and streamlining are completely eliminated, giving you a greater degree of confidence in your fit test decisions.
The Controlled Negative Pressure technology of the FitTester 3000 allows the mask to be challenged in ways that are impossible or at least impractical for other systems. Because we use negative pressure to replicate the negative force of inhalation, the FitTester 3000 can be set to increase the negative force in the mask to replicate breathing rates of over 100 liters of air exchanged per minute and measure the leak effect in only 8 seconds. Other systems might only be able to test at this level if you get the wearer to actually breathe at this high rate continuously for several minutes. Doing so with other systems would create great stress on the mask wearer!
CNP puts the PRESSURE on the MASK,.....NOT ON YOU!
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