Naturally smoke ventilation for buildings

[Tom Sutton]

I'm a student on the University of Wuppertal, Germany in the Field of Fire Safety Engineering I am studing for a Master-Graduation). Now I'm at the point to write the final exam called "Master-Thesis".
 
For this work I try to compare the normative standards for the dimensions of naturally smoke ventilation for buildings in the case of fire (that means that the smoke would drive of the building just because of the gradient of densities without any mechanical support) for different countries with a look for the physical backgrounds. For example in Germany we know the DIN 18232-2 with tables to find out the right size for roof vents in halls in dependency of the height of the hall which was designed with calculations by MRFC (zone model).

Do any standards exist in the UK to dimension a vent size for naturally smoke ventilation? Is it possible to get information about it on the internet (I don't think so)? In an earlier search for this case I found something about BS 7346 and BS 5588, but I'm not sure whether these are the right ones. If there are some standards: What's the legally basis to apply them?

I am reasonable certain that BS 5588 pt 9-1999 is of no use to him and BS 7346 pt 4 or pt 5 are the appropriate standards but which part is best suited for his purposes? Also is there any other documents that would be of assistance to him?

[Benzerari]

It's very interesting subject…, integrating air-conditioning and ventilation systems within FRA analysis..., and /or FAS…, it needs several research with different cases and environments to reveal certain substantial outcomes…etc

[CivvyFSO]

It's very interesting subject…, integrating air-conditioning and ventilation systems within FRA analysis..., and /or FAS…, it needs several research with different cases and environments to reveal certain substantial outcomes…etc

Pardon? Have you been smoking something again?

[Chris Houston]

I can't answer the question, but I would make the following observation having just spent some time surveying light industrial units in Germany.

Small light industrial units in Germany tend to have smoke vents in the roof.  Ones in the UK tend not to.  Ones in the Netherlands tend not to.  Fire detection in this type of units tends to be more common in the German units.  Generally the German ones seem best protected from fire out the three countries I have been surveying in.

[Roy]

Try CIBSE TM 19: 1995 Relationships for smoke control calculations. Though i'm not sure this can be downloaded for free.

[kurnal]

This topic is covered in a number of standards and guides.

In the UK all such designs would come under the umbrella of BS7974- Application of fire safety engineering principles to the design of buildings. In particular part 2 - the spread of smoke and toxic gases within and beyond the enclosure of origin.

BS publications are copyright and expensive but if on a bonafide course your universisty may give you access to the students database available in the UK- known as "athens". This gives free access to subnscribing institutions. Try a google on "athens" or ask your tutors.

The Building Research Establishment has sponsored a number of research projects into natural smoke ventilation- eg BRE 196 - shopping centres, BRE 258 - atrium buildings. Work carried out by H P Morgan, G O Hansel and J P Gardner  amongst others.

There is also the SFPE Handbook of Fire Protection Engineering (US Publication) (NFPA and SFPE)  and NFPA code 92B - guide for smoke management systems in Malls, Atrias and Large Areas.

(NB Not sure if some of the American documents are the most up to date)

If you contact the Fire Service College Moreton in Marsh UK you may be able to beg or borrow a set of their latest fire safety Engineering notes which are a good summary.

[CivvyFSO]

To size the vents you need a fire size, growing or controlled, depending on fuel load/type and any suppression systems installed. All this is detailed in the guides Kurnal mentioned, and this will assist in calculation the mass of smoke, and the bouyancy etc, from this you can then size the vents/create reserviors as needed. (Again, all detailed in the guides, of which I would choose BS7974 and the accompanying PD's)

BS7346 part 4 has many nice pretty pictures, this is intended for a controlled fire. i.e Supressed or controlled fire size, part 5 is similar but for time-dependent (i.e. growing) fires. Neither of these standards looks at supporting MOE or firefighting as such, they basically tell you the conditions without looking at tenability as 7974 does.

So basically, if the person is just looking for how to size vents according to different fires then BS7346 parts 4 and 5 will do, if they are looking at using vents to assist means of escape etc then BS7974 (or any of the others kurnal mentioned) should do.

FWIW, there are many conflicting accounts of the effects that suppression and ventilation systems have on each other, this may be something interesting to look at, or even just include, for this level of research.

[John Webb]

.....FWIW, there are many conflicting accounts of the effects that suppression and ventilation systems have on each other, this may be something interesting to look at, or even just include, for this level of research.

There were several BRE papers written by Dr Howard Morgan et al when he was at BRE regarding the interaction of sprinklers and vents, mostly in connection with advice to Building Regulation Div (DoE) F&RSs, Home Office and BSI. There were also large-scale experiments reported in two papers in Fire Science & Technology Vol 13 No.1 and No.2 1993; Part 1 looked at ceiling jet velocity and temperature measurements and Part 2 at the operation of sprinklers and the effect of venting with growing fires.

The most important finding was that opening vents would not cause undue delay in sprinkler operation and might even reduce the overall number of sprinklers that would operate. It's also necessary not to place sprinklers directly under vents where the downward spray would adversely affect the operation of the vent. (Dr Corrine Williams at BRE may be worth contacting on more recent work as I don't have anything after 1997.)

[Benzerari]

It's very interesting subject…, integrating air-conditioning and ventilation systems within FRA analysis..., and /or FAS…, it needs several research with different cases and environments to reveal certain substantial outcomes…etc

Pardon? Have you been smoking something again?

a bit of anti-hashish, 

By the way, approaching the BRE and getting support from them, is not a straight forward task, it has to have a convention between you, as student researcher and one of their promoter Dr or Professor in the field, the convention has to be through your institution or university and it takes time to get processed, and once the convention is ready, then you may have access to some of their sources...,
 

[kurnal]

.....FWIW, there are many conflicting accounts of the effects that suppression and ventilation systems have on each other, this may be something interesting to look at, or even just include, for this level of research.

There were several BRE papers written by Dr Howard Morgan et al when he was at BRE regarding the interaction of sprinklers and vents, mostly in connection with advice to Building Regulation Div (DoE) F&RSs, Home Office and BSI. There were also large-scale experiments reported in two papers in Fire Science & Technology Vol 13 No.1 and No.2 1993; Part 1 looked at ceiling jet velocity and temperature measurements and Part 2 at the operation of sprinklers and the effect of venting with growing fires.

The most important finding was that opening vents would not cause undue delay in sprinkler operation and might even reduce the overall number of sprinklers that would operate. It's also necessary not to place sprinklers directly under vents where the downward spray would adversely affect the operation of the vent. (Dr Corrine Williams at BRE may be worth contacting on more recent work as I don't have anything after 1997.)

John was the 1984 work by AJM Heselden "The Interaction of Sprinklers and Roof Venting in Industrial Buildings -the current knowledge" ISBN 0 85125 080 7 superseded by the  work that you mention?

[John Webb]

I should have said that the two papers in 'Fire Science & Technology' mentioned above were by Hinkley and Hansell (from Colt International) and Marshall and Harrison from the Fire Research Station(FRS).

And 'Yes' - Alan Heselden's work was superceded to a large extent by Howard Morgan's work - Howard was assistant to Alan and took over when Alan retired. Howard had the advantage of access to more computer models than Alan did. Peter Hinkley of Colt had worked for many years at FRS and continued to be involved after his retirement through his work for Colt.

[CivvyFSO]

and once the convention is ready, then you may have access to some of their sources...,

BRE have many published papers and guides which you can get your hands on through most technical indexes. IHS/CIS, Barbour etc.

[Tom Sutton]

Thanks to you all, I have sent off a response using the guidance you provided but have not received a reply or even thank you.