Tri-Tech Medical
Medical Gas Alarm Panels
Types of Medical Gas Alarms
Master
Area
Combination
DU/DC Series Area Alarms


Master alarms monitor
the ‘trunk’ source
equipment
Area alarms monitor the
‘branches’ zones or
areas – typically
downstream of zone
valve boxes
DU/DC Series Area Alarms


Up to 3 gas modules in
each vertical slot
Up to 14 gas modules in
one alarm panel
Compact design!
Tri-Tech
Medical Inc.
Medical Gas
Master Alarms
DU/DC Series Alarms



Up to 64 master signal
points per panel
16 master signal points
per slot
Positive confirmation of
normal condition (green
LED’s)
DU/DC Series Alarms

Combination 2 gas area
+ 16 signal master +
blank slot for future
expansion
DU/DC Series Alarms




Digital transducers may be
mounted in the alarm back
box or remotely up to 5,000
feet.
Twisted pair ‘fool-proof’
wiring
Designed to mount in a
standard 2 gang electrical
enclosure for added
protection
Gas specific electronic
recognition
DU/DC Series Alarms

Designed to mount in a
standard 2 gang
electrical enclosure for
added protection
DU/DC Series Alarms

Designed to mount in a
standard 2 gang
electrical enclosure for
added protection
DU/DC Series Area Alarms



2 slot = maximum of 4 transducers
3 slot = maximum of 6 transducers
5 slot = maximum of 9 transducers
DU/DC Series Alarms

User interface buttons

Silence
Test
Display history
Clear history
Display high set points ↑
Display low set points ↓
Display gas service →
Display transducer type ←







DU/DC Series Alarms







Gas module displays pressure
in .5 psi increments
Constant monitoring and
positive ‘Normal’ indication
Alarms for ‘High’ and ‘Low
line pressure. Range from 0.5
psi to 99.5 psi (ideal for lab &
hyperbaric applications too!)
Alarms for ‘Programming’
and /or ‘System’ error
Pockets in label provide
protected label slot for the
area being monitored
Do not require re-calibration
Calibration may be adjusted
using program keys (by one
person)
DU/DC Series Alarms






16 master signal points per
vertical slot
Constant monitoring of normal
condition
Each point is individually
programmable; green, red or may
be disabled – factory preset as red
with NO
Senses & displays NC or NO
circuits Pocket in label provides protected
label slot for the signal being
monitored
Pre-printed label sheet is provided
DU/DC Series Alarms



Up to 64 master signal
points per panel
16 master signal points
per slot
Positive confirmation of
normal condition (green
LED’s)
DU/DC Series Alarms

Pocket in label provides
protected label slot for
the signal being
monitored
DU/DC Series Alarms

Pocket in label provides
protected label slot for
the signal being
monitored
DU/DC Series Alarms





Button module circuit
board
Alarm notification
remote dry connectors
Dip switch for buzzer
decibel loudness setting
70, 80 or 90 db.
T-Net interface
connection
Programming button
keys (front side)
DU/DC Series Alarms




Master module
circuit board
Building
management
interface boards
(MCP boards)
Dip switch for
programming or run
mode
3 character 7 segment
display for easy
programming
DU/DC Series Alarms





Gas module circuit board
Transducer connectors
Low line pressure remote
dry connectors
High line pressure remote
dry connectors
Dip switch for programming
or run mode
DU/DC Series Alarms




Low line pressure
remote dry connectors
High line pressure
remote dry connectors
Orange & blue = line
pressure low
Red & green = line
pressure high
T-Net Medical Gas Alarms
Information Management System
DU/DC Series Alarms

Ethernet interface
board, bracket & ribbon
cable
DU/DC Series Alarms

Wireless interface
board, antennae, bracket
& ribbon cable
Thank You
NFPA 5.1.9 Level 1 Warning Systems








All master, area & local alarm systems used for medical
gas & vacuum systems shall include the following:
Separate visual indicators for each condition monitored
(except as permitted in 5.1.9.5.2)
Visual indicators that remain in alarm until the situation that
had caused the alarm is resolved
A cancelable audible indication of each alarm condition that
produces a sound with a minimum of 80 dBA @ 3 ft
A means to visually indicate a lamp or LED failure
Visual & audible indication that the wiring to an alarm
initiating device is disconnected
Labeling of each indicator, indicating the condition monitored
Labeling of each alarm panel for its area of surveillance
NFPA 5.1.9 Level 1 Warning Systems






Re-initiation of the audible signal if another alarm condition
occurs while the audible alarm is silenced
Powered by the Life Safety branch of the emergency electrical
system
Power for local alarms, dew point sensors, & CO sensors
permitted to be from the same essential electrical branch as is
used to power the air compressor
Wiring from switches or sensors that is supervised or protected
as required by Sect 517.30 (C) (3) of NFPA 70
Assurance by the responsible authority of the facility that the
labeling of the alarms, where room #’s or designations are
used, is accurate & up-to-date
Provisions for automatic restart after a power loss of 10
seconds without giving false signals or requiring manual reset
NFPA 5.1.9.2 Master Alarms




A master alarm system shall be provided to monitor
the operation and condition of the source supply, the
reserve source, and the pressure in the main lines of
each medical gas & vacuum piping system
The master alarm system shall consist of two or more
alarm panels located in at least two separate locations
as follows:
One master alarm panel shall be located in the office
or work space of the on-site individual responsible for
the maintenance of the medical gas & vacuum
systems
The second master alarm panel shall be located in an
area of continuous observation





5.1.9.2.2 A centralized computer system shall be
permitted to be substituted for one of the master
alarms, if it complies with 5.1.9.4
5.1.9.2.3 The master alarm panels shall connect
directly to the alarm devices they monitor
5.1.9.2.3.1 Master alarm signals shall not be relayed
from one master alarm panel to another
5.1.9.2.3.2 Where multi-pole alarm relays are used to
isolate the alarm initiating signals to master alarm
panels, the control power source for the relays shall
be independent of any of the master alarm panels
5.1.9.2.3.3 Multiple master alarms shall be permitted
to monitor a single initiating device
5.1.9.2.4 Master alarm panels for medical gas & vacuum
systems shall each include the following signals:





An alarm indication when the medical-surgical vacuum
pressure in the main line of each vacuum system drops to or
below 300 mm (12 inHg)
An alarm indication(s) from the local alarm panel(s) as
described in 5.1.9.5.2 to indicate when one or more of the
conditions being monitored at a site is in alarm
A medical air dew point high alarm from each compressor site
to indicate when the line pressure dew point is greater than ±
2° C (+35° F)
A WAGD low alarm when the WAGD vacuum level or flow
is below effective operating limits
An instrument air dew point high alarm from each compressor
site to indicate when the line pressure dew point is greater than
-30°C (-22°F)
5.1.9.2.4 Master alarm panels for medical gas & vacuum
systems shall each include the following signals:




An alarm indication for cylinder reserve pressure low when
the content of a cylinder reserve header is reduced below one
day’s supply
For bulk cryogenic liquid systems, an alarm when or at a
predetermined set point before the reserve supply contents fall
to one day’s average supply, indicating reserve low
Where a cryogenic liquid storage is used as a reserve for a
bulk supply system, an alarm indication when the gas pressure
available in the reserve unit is below that required for the
medical gas system to function
An alarm indication when the pressure in the main line of each
separate medical gas system increases 20 % or decreases 20%
from the normal operating pressure
5.1.9.2.4 Master alarm panels for medical gas & vacuum
systems shall each include the following signals:



An alarm condition when or just before changeover occurs in a
medical gas system that is supplied by a manifold or other
alternating-type bulk system that has as a part of its normal
operation a changeover from one portion of the operating
supply to another
An alarm indication for a bulk cryogenic liquid system when
the main supply reaches an average day’s supply, indicating
low contents
An alarm indication when or just before the changeover to the
reserve supply occurs in a medical gas system that consists of
one or more units that continuously supply the piping system
while another unit remains as the reserve supply & operates
only in the case of an emergency

5.1.9.2.5 The alarm indications required in
5.1.9.2.4(7) and 5.1.9.2.4(8) shall originate
from sensors installed in the main lines
immediately downstream of the source valves.
Where it is necessary to install a main line
valve in addition to a source valve, the sensors
shall be located downstream of the main valve.
NFPA 5.1.9.3 Area Alarms
Area alarm panels shall be provided to monitor
all medical gas, medical-surgical vacuum, and
piped WAGD systems supplying anesthetizing
locations, and other vital life support and
critical areas
 5.1.9.3.1 Area alarms shall be located at a
nurse’s station or other similar location that
will provide for surveillance





5.1.9.3.4 Sensors for area alarms shall be located
as follows:
Vital life support & critical areas shall have the alarm
sensors installed on the patient or use side of any of
the individual zone valve box assemblies
Areas for anesthetizing gas delivery shall have the
sensors installed either on the source side of any of
the individual room zone valve box assemblies or on
the patient or use side of each of the individual zone
valve assemblies
The placement of the sensors shall not be affected by
valves located in areas accessible to authorized
personnel only, such as service valves.
5.1.9.3.2 Area alarm panels for medical gas
systems shall indicate if the pressure in the
lines in the area being monitored increases or
decreases by 20% from the normal line
pressure.
 5.1.9.3.3 Area alarm panels for medicalsurgical vacuum systems shall indicate if the
vacuum in the area drops to or below 300 mm
(12 in Hg).
