1. Aspirated Smoke Detection
By: Andrew Turchet

2. Aspirated Smoke Detection
What is Aspirated Smoke Detection?
In its simplest form a smoke detector
Known as:
ASD (Aspirated Smoke Detection)
ASSD (Air Sampling Smoke Detection)

3. Aspirated Smoke Detection
How does ASD work?

4. Aspirated Smoke Detection
ASD technology utilizes collective air sampling vs. point detection
A sample of air is collected from multiple sampling holes
Sampling pipe
VESDA
LaserPLUS 88

5. Aspirated Smoke Detection
Basic rule of application
Areas of coverage and spacing are the same for both
Sample Hole =

6. Aspirated Smoke Detection
How does ASD work?

7. Aspirated Smoke Detection
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

8. Aspirated Smoke Detection
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.

9. Aspirated Smoke Detection
Early Warning Applications
Telecommunications
IT / Data Centres
Semi-conductor Fab
High Value Storage – museums, galleries, libraries, archive.

10. Aspirated Smoke Detection
Telecom & Data Centre
High valued equipment
Emergency services
Critical data storage
Down-time causes loss of revenue
Early warning reduces the risk from fire

11. Aspirated Smoke Detection
NFPA 75
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 detection–type 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
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.
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 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.

12. Aspirated Smoke Detection
NFPA 76
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.
* Use of VEWFD systems with an alert (pre-alarm) condition shall provide for an initial response by authorized personnel prior to fire department notification.
VEWFD Sensor and Port Installation.
* Every type of sensor and port installed in an area shall be limited to a maximum coverage area of 18.6 m2 (200 ft2).
* 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.
* 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.
Maximum transport time from the most remote port to the detection unit of an air- sampling system shall not exceed 60 seconds.

13. Aspirated Smoke Detection
Consequences of an incipient fire
“95% of all fire damage within facilities housing electronic equipment is non-thermal”
* US Federal Commission of Communications

14. Aspirated Smoke Detection
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.

15. Aspirated Smoke Detection
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

16. Aspirated Smoke Detection
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

17. Aspirated Smoke Detection
Atriums

18. Aspirated Smoke Detection
Atriums
Stratification
Thermal lift
Dilution in large volume
Smoke movement by mechanical ventilation

19. Aspirated Smoke Detection
Atriums
Sampling at multiple points

20. Aspirated Smoke Detection
High equipment heat output + High cooling demand = High air change rates

21. Aspirated Smoke Detection
Air Change Rate Calculation
Air change rate needs to be calculated for all protected areas (i.e. under-floor, room, above ceiling)
Determine volume of all protected spaces
Sum total CFM for the HVAC system serving the space + fresh air
Air Change/Hour = Total CFM x 60min
Volume

22. Aspirated Smoke Detection
Smoke Detector Spacing Based on Air Movement
Min/Changes Changes per Hour m2 spacing ft2 spacing

23. Aspirated Smoke Detection
Access is Difficult
Remote testing
Detector and test point can be remotely located to facilitate maintenance
Fewer test points

24. Aspirated Smoke Detection
Applications Where Access is Difficult
Atriums
Energized spaces
Prison Cells
Confined spaces (crawl, attic)
Hazardous areas
Elevator shafts
Congested ceilings

25. Air-Sampling Detection Overview
Annual inspection is performed at most remote sampling hole on each pipe
Last Hole (Test Point)
Air-Sampling Detector
(Test Point)
Record transport time and compare

26. Aspirated Smoke Detection
Atriums
Testing done at most remote point

27. Aspirated Smoke Detection
Prison Cells
Sampling is performed in exhaust duct of cell.
Testing can be done remotely

28. Aspirated Smoke Detection
Prison Cells
Sampling point concealed behind return air grill
Out of site out of mind

29. Aspirated Smoke Detection
Correctional sampling point alerts when blocked

30. Aspirated Smoke Detection
Congested Ceiling Spaces

31. Aspirated Smoke Detection
Performing annual inspections can be difficult

32. Aspirated Smoke Detection
Access to under-floor detectors is difficult

33. Aspirated Smoke Detection
Thank you!
Andrew Turchet
Xtralis (manufacturers of VESDA)