fire protection when installing fans

[ianphilip007]

hi there

just been reading thru the ESC best practice guide 5 " Electrical installations and their impact on fire performance" it indicates that when running ducting from a bathroom fan vent along a void parrellel to joists in a floor or loft space that the joists have to be provided with fire protection for example lined with plasterboard. to protect joists from fire entering the vent and burning thru duct.

i have never seen this done,ducting is usally just laid accross the insulation covering the joists. any views or examples of what you do?

 

[ianphilip007]

any thoughts ??

 

[mogga]

if your going through firewalls or fire celing you could fit solid 4inch pipe with fire collar on it the type that contracts if theres a fire

 

[Engineer54]

Anyone know, or have ever heard of a fire starting in a Bathroom?? Nope, ... didn't think so!!! Not surprising really seeing as the vast majority are fully tiled affairs....

 

[ianphilip007]

i agree engineer 54 very unlikely, just the document i was refering to did not distinguish between different rooms. it was the reference to fire protecting the joists that seemed odd to me. as mogga suggests if going thru a firewall or ceiling i would usualy fit a fire sleeve round the vent. just seems a little over the top.

 

[Engineer54]

Agree, i've never seen such protection for these small fan air ducts in a domestic installation, and i doubt very much if anyone else has either. If they were that concerned about these plastic air ducts, they should insist on metal ducting in loft spaces.
Then i suppose they would start calling for fire dampers!!!! ...lol!!

 

[ianphilip007]

ive never seen fire protection fitted on a 4inch fan in any domestic property i have worked on either engineer. have checked availability of fire collars on the interweb. the are available but they are not cheap. as stated before fire protection of ducting,vents and joists seems ott especially if no considered risk.

 

[malcolmsanford]

The interesting part about that is the "running parallel" to joists, what if you were running it over the joists??

 

[Paul.M]

Below is a report from the Yorkshire Evening Post.


Sponsored by
Leeds hotel restaurant evacuated after kitchen fire

Published on Thursday 6 September 2007 09:03
A hotel restaurant had to be evacuated after a kitchen blaze broke out.
Thick clouds of black smoke were seen pouring from The Golden Lion Hotel, a four storey public house and hotel on Lower Briggate, shortly after 7pm last night.
Staff and guests - which included 49 British tourists staying at the hotel - emptied into the streets where they watched in horror as emergency services arrived.
Police sealed off the area and redirected motorists while fire fighters tackled the fire which had started in the kitchen ducting and spread to a first floor courtyard.
Eric Roberts, leader of the Best of Yorkshire holiday tour, was eating
in the restaurant with his group of 48 holidaymakers when the fire broke out.
"We were having a meal, I spotted smoke in the kitchen and checked with the chef who signalled that we should all go outside.
"We followed the hotel's emergency procedures, which worked perfectly."
Crews from Leeds and Hunslet attended.


What this news article doesn't tell you is the fire started on the open grill, the flames got sucked up the ventilation and set fire to the hotel room above. A very expensive mistake, smoke damage to half of the hotel. £3M refit and a change of name all because the chef burnt the steaks.

 

[ianphilip007]

well the guidance does refer to the ducting running transverse or accross the joists as you suggest malcom, it states that the amount of joist matierial that would have to be cut away would significantly weaken the structure, and to seek expert guidance on the structure and fire seperation measures. the guidance also illustrates your point paul. it illustrates a a bathroom room fan in extract mode at the time of a fire, therefore drawing the fire into the duct and void above.

i can see the possible dangers, just never seen protection of the void as suggested in the guidance, can i ask if anyone or evryone is following this guidance re protecting the void

 

[mogga]

the Commercial kitchen fans igniting has and will continue to happen due to lack of maintenance and build up of a film of fat and pockets of grease in the syatem this happened at our local a few years back they had a 6monthly scheduled deep clean due in 2 weeks but this didnt take into acount the 4months worth of grilled burgers sold in 2 weeks not only adding to the grease build up but as they opened longer this grease was viscous rather than gel like hence taking less to ignite it These sort of things are forgotten along with dust wich given correct conditions can be explosive ie try throwing a hand full of dust on an open fire and watch the results