• Where maximum use concentrations are exceeded
• Full facepiece: where the contaminant concentration
is 1000 times the exposure limit.
• Headgear: where the contaminant concentration is
25 times the exposure limit.
• Where the limitations outlined in the applicable
NIOSH approval are exceeded.
• Where any applicable limitation contained in a
standard established by a regulatory agency (such
as OSHA) with jurisdiction over the wearer is
exceeded.
A listing of acceptable exposure limits is available from
the American Conference of Governmental Industrial
Hygienists (ACGIH); Occupational Safety and Health
Administration (OSHA); National Institute for Occupatio-
nal Safety and Health (NIOSH) and American Industrial
Hygiene Association (AIHA).
The SR 500 requires the use of one lithium ion (Li-ion)
type battery heavy duty HD; one of several alternate
respiratory inlet coverings - half mask, full face mask,
hoods, and visor; and two (2) filters or combined filters/
cartridges. The SR 500 can be operated for up to 13
hours.
The same control button is used for starting, stopping
and selection of operating status. The SR 500 Fan Unit
has a display with the following symbols:
• Small fan symbol that lights up with a green light
during normal operation 6.2 CFM (175 l/min).
• Bigger fan symbol that lights up with a green light
during boosted operation 7.9 CFM (225 l/min).
• Triangle that lights up with a red light if the air flow
should cease or if the filters are clogged.
• Battery symbol lights up to indicate the battery
capacity at start and when the battery capacity is
low.
To operate the fan unit:
• Start the fan by pressing the control button.
• After the button has been pressed, a programmed
test will be run on the fan unit, during which the
symbols on the display will light up, the sound signal
will sound and the vibrator will vibrate twice. Fig.
• Battery symbol lights up and indicates the battery
capacity.
o Lights green: > 70 %
o Flashing green: 50-70 %
o Lights yellow: 20-50 %
o Flashing red: < 20 %
• After the internal test, all symbols will be extinguis-
hed except the small green fan symbol. This
indicates normal operating status with a flow of at
least 6.2 CFM (175 l/min).
• If the button is pressed again, boosted operating
status will be activated, with a flow at least 7.9 CFM
(225 l/ min). This is indicated by the larger green fan
symbol lighting up.
• To revert to normal operation, press the control
button once again.
• To switch off the fan unit, keep the control button
depressed for about two seconds.
Air flow rates
On normal operation, the fan delivers at least 6.2 CFM
(175 l/ min), and on boosted operation, at least 7.9 CFM
(225 l/min). The automatic flow control system of the fan
unit maintains these flows constant throughout the
operating time. The SR 500 is equipped with automatic
6
air flow control, with compensation for air pressure and
temperature, and initiates an alarm by vibration and
sound/light signals in the event of an obstruction in the
air flow.
SR 500 Warning System/Alarm Signals
If the air flow should drop below the preselected value
6.2 CFM or 7.9 CFM (175 or 225 l/min), the SR 500 Fan
Unit will provide the following alarms:
• A pulsating sound signal will be heard.
• The built-in vibrator will be activated.
• The red warning triangle of the display will flash.
WARNING - Immediately interrupt the work, leave
the area, and inspect the equipment. Do not
remove the SR 500 respiratory inlet covering while
you are in contaminated atmosphere.
If the PARTICULATE filters are clogged, this is indicated
in the following way:
• A continuous sound signal will be heard for five
seconds.
• The red warning triangle in the display will flash.
• The built-in vibrator will be activated for five seconds.
• The warning triangle will flash continuously, whereas
the sound signal will be repeated at intervals of 80
seconds.
WARNING - Immediately interrupt the work, leave
the area, and inspect the equipment. Do not
remove the SR 500 respiratory inlet covering while
you are in contaminated atmosphere.
If the battery capacity is low - the battery capacity has
dropped to about 5 % of the original charge, this is
indicated as follows:
• A sound signal will be repeated twice at intervals of
two seconds.
• The red battery symbol of the display will flash.
• The built-in vibrator will be activated twice at
Fig.
17.
intervals of two seconds.
• The battery symbol will flash continuously, whereas
the sound signal and the built-in vibrator are
repeated at intervals of 30 seconds until about one
18.
minute remains before the battery would be fully
discharged. The sound signal then changes to an
intermittent signal.
WARNING - Immediately interrupt the work, leave
the area, and inspect the equipment. Do not
remove/doff the SR 500 respiratory inlet covering
while you are in contaminated atmosphere.
4.2 Belt
There are three (3) belt assemblies that can be used
with the SR 500 Fan Unit based on the material used n
the construction of the belt: rubber (SR 503), leather
(SR 504) and nylon (SR 508). The belt consists of two
halves that can be fitted to the rear of the fan unit
without tools. To assemble proceed as follows:
• Place the fan upside down. Fig 4.
• Insert the three tongues of the belt half into the slot
in the fan. The folded end of the strap should face
upwards. Study the illustration carefully to ensure
that the belt will not end up upside down or back to
front. Fig 4.
• Press down the three lips locking the belt half.Fig.
• Proceed in the same way with other half of the belt.
• The length of the belt can easily be adjusted by
pulling in or slackening the strap ends.
5.