By: Andrew Turchet Slide 2 What is Aspirated Smoke Detection? In
its simplest form a smoke detector Known as: ASD (Aspirated Smoke
Detection) ASSD (Air Sampling Smoke Detection) Slide 3 How does ASD
work? Slide 4 ASD technology utilizes collective air sampling vs.
point detection A sample of air is collected from multiple sampling
holes Sampling pipe VESDA LaserPLUS 88 Slide 5 = Sample Hole Basic
rule of application Areas of coverage and spacing are the same for
both Slide 6 How does ASD work? Slide 7 Why use ASD? Early warning
achieved thru increased sensitivity and active air sampling
Difficult to detect smoke Stable performance in adverse
environments Access is difficult Slide 8 Early Warning Widest
sensitivity range available can achieve %obs/ft values a 1000 times
greater than conventional photo-electric Active vs. Passive air
sampling can capture smoke Collective sampling gives the advantage
of pulling together quantities of smoke from many sampling holes.
Collectively early warning notification can be achieved. Slide 9
Early Warning Applications Telecommunications IT / Data Centres
Semi-conductor Fab High Value Storage museums, galleries,
libraries, archive. Slide 10 Telecom & Data Centre High valued
equipment Emergency services Critical data storage Down-time causes
loss of revenue Early warning reduces the risk from fire Slide 11
8.2* Automatic Detection Systems. Automatic detection equipment
shall be installed to provide early warning of fire. The equipment
used shall be a listed smoke detectiontype system and shall be
installed and maintained in accordance with NFPA 72, National Fire
Alarm Code. 8.2.1* Automatic detection systems shall be installed
in the following locations: (1) At the ceiling level throughout the
information technology equipment area (2) Below the raised floor of
the information technology equipment area containing cables (3)
Above the suspended ceiling and below the raised floor in the
information technology equipment area where these spaces are used
to recirculate air to other parts of the building 8.2.2 Where
interlock and shutdown devices are provided, the electrical power
to the interlocks and shutdown devices shall be supervised by the
fire alarm control panel. 8.2.3 The alarms and trouble signals of
automatic detection or extinguishing systems shall be arranged to
annunciate at a constantly attended location. A.8.2 Fire detection
and extinguishing systems should be selected after a complete
evaluation of the exposures. The amount of protection provided
should be related to the building construction and contents,
equipment construction, business interruption, exposure, and
security need. For amplification of the important need of fire
protection, see Chapter 4. A.8.2.1 The detection system selection
process should evaluate the ambient environmental conditions in
determining the appropriate device, location, and sensitivity. In
high airflow environments, air-sampling detection devices should be
considered. Slide 12 6.8.6.1 General. Facilities containing greater
than 232 m2 (2500 ft2) of signal-processing equipment area shall be
provided with a very early warning fire detection (VEWFD) system
for detection and alarm processing in accordance with Chapter 8.
8.4.1.3* Use of VEWFD systems with an alert (pre-alarm) condition
shall provide for an initial response by authorized personnel prior
to fire department notification. 8.5.3.1.2 VEWFD Sensor and Port
Installation. 8.5.3.1.2.1* Every type of sensor and port installed
in an area shall be limited to a maximum coverage area of 18.6 m2
(200 ft2). 8.5.3.1.2.2* Where two levels (high and low) of ports or
sensors are provided, each level shall be limited to a coverage of
37.2 m2 (400 ft2) or less per port or sensor. (A) The coverage
limitation between high and low levels shall be limited to 18.6 m2
(200 ft2) or less providing for staggered port or sensor
arrangements between each level. 8.5.3.1.2.3* Sensors or ports
shall be installed to monitor return air from the space. (A) Where
stand-alone packaged HVAC units are installed, sensors or ports
shall be installed where return air is brought back to the unit.
(B) Sensors or ports shall be installed such that each covers no
greater than 0.4 m2 (4 ft2) of the return air opening. 8.5.3.1.2.6
Maximum transport time from the most remote port to the detection
unit of an air- sampling system shall not exceed 60 seconds. Slide
13 Consequences of an incipient fire * US Federal Commission of
Communications 95% of all fire damage within facilities housing
electronic equipment is non-thermal Slide 14 Large amounts of
plastics in cabling, circuit boards, etc. Smoldering fire releases
harmful corrosive by- products (HF, HBr, ZCl). Can lead to
immediate or unexpected failure. Slide 15 Difficult to Detect Smoke
Large open spaces Dilution High air change rates and distribute and
dilute smoke Background smoke Adjusting for high ambient non-fire
related smoke Slide 16 Difficult to Detect Smoke Applications
Atriums Power generation facilities Data Centre Water, waste and
sewage treatment facilities Industrial mining, steel mills, petro-
chemical, wood, pulp and paper Slide 17 Atriums Slide 18
Stratification Thermal lift Dilution in large volume Smoke movement
by mechanical ventilation Slide 19 Atriums Sampling at multiple
points Slide 20 High equipment heat output + High cooling demand =
High air change rates Slide 21 Air Change Rate Calculation 1. Air
change rate needs to be calculated for all protected areas (i.e.
under-floor, room, above ceiling) 2. Determine volume of all
protected spaces 3. Sum total CFM for the HVAC system serving the
space + fresh air 4. Air Change/Hour = Total CFM x 60min Volume
Slide 22 Smoke Detector Spacing Based on Air Movement Min/Changes
Changes per Hour m2 spacing ft2 spacing 16011.61125 23023.23250
32034.84375 41546.45500 51258.06625 61069.68750 78.681.29875
87.583.61900 96.783.61900 10683.61900 Slide 23 Access is Difficult
Remote testing Detector and test point can be remotely located to
facilitate maintenance Fewer test points Slide 24 Applications
Where Access is Difficult Atriums Energized spaces Prison Cells
Confined spaces (crawl, attic) Hazardous areas Elevator shafts
Congested ceilings Slide 25 Last Hole (Test Point) Air-Sampling
Detector (Test Point) Slide 26 Atriums Testing done at most remote
point Slide 27 Prison Cells Sampling is performed in exhaust duct
of cell. Testing can be done remotely Slide 28 Prison Cells
Sampling point concealed behind return air grill Out of site out of
mind Slide 29 Correctional sampling point alerts when blocked Slide
30 Congested Ceiling Spaces Slide 31 Performing annual inspections
can be difficult Slide 32 Access to under-floor detectors is
difficult Slide 33 Thank you! Andrew Turchet Xtralis (manufacturers
of VESDA) 416-580-9139 [email protected]
