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2
Principle o
f Oper
ation / Battery P
ack
EVAHL Series - Principle of Operation
The EVAHL Series Powered Air-Purifying Respirator (PAPR) System is configured in
six parts:
1. The blower and belt assembly:
EVAHL1 Blower Unit
EVABELT1 or EVABELT2 Comfort Belt, Decon Belt
PA1AFI Air Flow Indicator
2. The battery pack (Part No. EVAHLBAT1). One fully charged pack will power the blower
for approximately 4 to 10 hours depending upon factors such as speed, cartridge
selected and cartridge loading.
3. The breathing tube, which is available in three different types and three lengths:
PAHBT Powered Air Hood Breathing Tube Assembly (standard length - 26")
PAHBTXS Powered Air Hood Breathing Tube Assembly (short length - 22")
PAHBTXL Powered Air Hood Breathing Tube Assembly (long length - 32")
PA1BT Hood breathing tube assembly with clamp (standard length - 26")
PA1BTXS Hood breathing tube assembly with clamp (short length - 22")
PA1BTXL Hood breathing tube assembly with clamp (long length - 32")
PA20LFBT Loose fitting facepiece breathing tube assembly (standard length - 32")
PA20LFBTXS Loose fitting facepiece breathing tube assembly (short length - 26")
PA20LFBTXL Loose fitting facepiece breathing tube assembly (long length - 38")
4. The High Efficiency Particulate Arrestance (HEPA) filter or chemical filter cartridge.
5. The hood with headband suspension (except for the RT Series) and/or hard hat, or
loose fitting facepiece. The following hood models may be used with the EVAHL Series
blower unit:
RT1, RT1T Hood with long inner and outer bib (NIOSH approved for use without a
headband suspension)
RT2, RT2T Hood with long inner and outer bib (NIOSH approved for use without a
headband suspension)
RT3, RT3T Hood with long inner and outer bib (NIOSH approved for use without a
headband suspension)
RT4, RT4T Hood with long inner and outer bib (NIOSH approved for use without a
headband suspension)
20TJN, 20TJNT Hood
20TICN, 20TICNT Hood with inner bib
20TICH, 20TICHT Hood for use with Bullard hard hat
20TICSN, 20TICSNT Hood with taped and sealed seams
20SICN, 20SICNT Hood with taped and sealed seams
20SICVN, 20SICVNT Hood with taped and sealed seams and PVC lens
20SICH, 20SICHT Hood with taped and sealed seams for use with Bullard hard hat
20SICVH, 20SICVHT Hood with taped and sealed seams and PVC lens for use with
Bullard hard hat
20LFM Loose fitting facepiece, medium size
20LFL Loose fitting facepiece, large size
20LFXL Loose fitting facepiece, extra large size
20LF2S Loose fitting facepiece (narrow profile), small size
20LF2M Loose fitting facepiece (narrow profile), medium size
20LF2L Loose fitting facepiece (narrow profile), large size
6. The Battery Charger:
EVAHLSMC Quick charger, single port
EVAHLGC Gang charger, six port
The blower unit draws in ambient air through the cartridges. The purified air is blown
into the wearer’s hood through the breathing tube. A flow indicator is provided to check
that there is an adequate volume of air available to the wearer prior to use. The system is
designed to operate at a minimum air flow of approximately 7 cubic feet of air per minute
(198 liters per minute) in the hood under normal use on the standard speed setting, and
8.5 cubic feet of air per minute (240 liters per minute) in the hood under normal use
on the high speed setting. A feedback loop from the Mass Flow Sensor to the impellor
continually monitors and adjusts the air flow to keep it constant at the design set point.
The units are designed for use at temperatures from 23ºF to 129ºF (-5ºC to 55ºC).
A high temperature alarm will sound at 122ºF (50ºC).
The battery pack mounts in a compartment on the back of the blower. A fully charged
battery pack will power the blower for approximately 4 to 10 hours depending upon
factors such as speed selected, cartridge selected, and filter/cartridge loading.
The EVAHL Series Blower is equipped with two alarms: A 77 db continuous alarm will sound
when the air flow falls below approximately 185 lpm and a 77db intermittent chirp alarm will
activate to indicate that the battery has approximately 15 minutes of remaining capacity.
Type C Airline Respirators -
CC20 Series (TC-19C-154), RT Series (TC-19C-412)
Most of the same headpieces approved for use with the CC20 and RT Series of supplied
air respirators (SAR) are also approved for use with the EVAHL Series of powered air-
purifying respirators. CC20 and RT Series respirators provide a high level of respiratory
protection and user comfort over long work periods, in a wide variety of hazardous
environments.
The CC2 and RT SAR air flow control devices and other components are described in the
CC20 and RT Series User Instructions.
Battery Pack
One fully charged battery pack will power the blower for approximately 4 to 10 hours
depending upon factors such as speed selected, cartridge selected and filer/cartridge
loading.
WARNING:
EXPLOSION HAZARD
• Only use Bullard battery part number: EVAHLBAT1. Substitution of any other
battery pack may impair suitability for Division 2.
• Do no charge battery packs in hazardous locations.
• Only charge using Bullard Desktop battery pack chargers.
• Do not insert or remove the battery pack unless the area is known to be free
of ignitable concentrations.
NOTE
The battery has built-in short circuit protection. In the event of a short circuit, an
internal polyfuse will trip. The fuse will reset itself within 5-10 seconds allowing the
battery to resume normal operation.
To charge the battery pack, do the following:
• Use a flat head tool to release the battery from the blower. (See Figure 1.)
• Place battery into the charging port of the battery charger. (See Figure 2.)
• Connect the battery charger to a 110-volt AC electrical outlet.
• Charge the battery pack for approximately 4 hours. While the battery is charging, the
light on the charger will remain red. The charger light will illuminate green when charging
is complete.
Table-top gang chargers with 6 ports are also available.
Figure 1
Figure 2
