Print this pageSmoke detection for ceilings with beams
 |
Ceilings with beams need special consideration when designing a smoke detection system as the 'pockets' formed between the beams can trap smoke. Fire codes such as the US National Fire Protection Association (NFPA) recognize this problem and have recommendations in place e.g.NFPA 72. These recommendations include placing a smoke detector in every pocket. In a large room with many beams, the cost of installing and then maintaining such a smoke detector system becomes prohibitive. |
Research on fire protection systems for ceilings with exposed beams
Xtralis fire protection engineering team undertook a research project to determine:
- Does the presence of ceiling structures such as beams or joists affect smoke detection performance?
- If so, is spot detector performance more or less susceptible than that of air sampling detector systems?
- How does the arrangement and location of detection points influence performance?
- What is the most cost effective fire protection system for areas with such ceiling structures?
Supervised by Australia's government research organization - CSIRO, the fire protection engineering team conducted a series of in-situ tests as well as extensive computer modelling of smoke movement in rooms with exposed ceiling beams.
Findings of the research
The key findings of the research were:
- Exposed beams or joists deeper than 1 ft (30 cm) affect the movement of smoke at ceiling level. Smoke is trapped between the beams, making it necessary to have a spot detector in every inter beam space, regardless of the dimensions of the spaces.
- Air sampling smoke detectors detected smoke earlier and more reliablity than point detectors on ceilings with exposed beams.
- Spot detectors installed on the underside of the beams did not reliability detect smoke. Spot detectors must be installed on the ceiling.
- Placing the sample pipes of an air sampling smoke detection system ( such as a VESDA system), with sample holes at appropriate spacing will always provide the required level of fire protection.
- With sample pipes installed under the beams, an air sampling smoke detection system is considerably cheaper to install and maintain than spot detectors installed in every beam pocket (less than 20% of the price in the example room studied)
The insitu tests demonstrated that spot detectors were needed in each beam 'pocket'.
What does this all mean?
If you have a room with solid exposed beams that are more than 1 ft (30 cm) deep then a VESDA air sampling smoke detection system offers better smoke detection at a considerably cheaper price than spot detectors in every pocket.
By using a performance based design, supported by the research conducted by Xtralis engineers, you can design a code-compliant smoke detection system that offers the very early warning of a VESDA system.
Learn more
In or out of pocket? What's the best smoke detection system for ceilings with beams?
This White paper summarizes the results of the research into smoke detection performance on ceilings with exposed beams. You will need an access level other than 'Reg' to access this white paper. more
Need help designing a VESDA system?
Contact us and an engineer will be able to assist. You can also obtain the full scientific reports of the tests if you need them.
Xtralis | Your Privacy | Terms of use | Contact us
