Temporary Structures

[Tom Sutton]

I received the following enquirey

"A temporary building similar to a marquee, it has a lightweight metal frame and composite/glass wall panels with a roof constructed of tensioned canvas type material over a metal frame.  The interior has a taught fabric covering to conceal the roof structure.  The material has been tested to BS 5867."
 
Is this the appropriate standard and adequate for this scenario or should BS 78837 or BS EN 13782:2005 or BS 5438:1989 be considered, where do you start?

[kurnal]

I presume we are discussing  an existing temporary structure rather than designing a new one?

 Start of with what you have and what it is to be used for. It makes no odds really what standards could be quoted, its not going to make a jot of difference  to an existing temporary  structure.

Ask to see the test certificate that they do have for both the structure and the inner linings. The treatments deteriorate with time, exposure to weather and laundering, and need to be kept up to date. BS5867 only applies to curtains and drapes.

If its an entertainment event then the guides may help - the outdoor venues guide, and the old purple event safety guide HSG 195  may be of use.(I think the free download link may not be the latest version- check with HSE website)

http://www.communities.gov.uk/documents/fire/pdf/158379.pdf

http://www.city.ac.uk/safety/dps/H%20&%20S%20Information/HSG195%20Event%20Safety%20Guide.pdf

[Tom Sutton]

Thanks kurnal but the problem seems to be the use of curtain material in an unusual location if it was in the vertical plane then that is how it is tested no problem. But in this case it’s acting like a ceiling to the canvas roof and which only bears some relationship to how it was tested. I think some time ago there was a night club that had carpet tiles on the walls which resulted in a rapid spread of fire although they had been subjected to the hot nut test, but not in a vertical plane. Consequently does this invalidated any tests, if so which tests should be used or should you consider ad hoc testing?

Most of the specific guidance gives a list of international standards and take your pick. I personally would accept BS 5867 as being best suited for this situation.

[kurnal]

I would go for ad hoc testing anyway irrespective of what the supplier claims. Its surprising what this shows up - I usually make a judgement based on a number of  match tests. Completely unscientific but its surprising what you find as a result.

Many local authorities still issue guidance on marquees based on standard advice- heres an example dating back to 2008 so is about the most recent you will find:
3.1. The marquee must be manufactured or treated so as to reduce
the flame spread hazard associated with the use of large areas of
textile materials.

3.2. New fabrics are to be inherently or durably flame retarded
when tested to BS 7837: 1996. However, fabrics tested to the following national standards are also acceptable:-
British Standard 5438, Tests 2A and 2B,
British Standard 7157,
French Standard NFP.92503, Performance Level M2,
German Standard DIN 4102, Part 1, Performance Level B1,
Italian Standard UNI 9174, Performance Level M2,
USA Standard NFPA 701, Large scale test.

3.3. The use of structures manufactured to British Standard 5438:
1989 are still deemed acceptable at this time.

3.4. All unattached lining materials are to comply with British
Standard 5867: Part 2, fabric type B, the specification for fabrics for
curtains and drapes.

3.5. Linings for marquees and large tents may be suspended using
ropes constructed from man-made or natural fibres and may be
laced together using the same materials. Linings are only to be used
if constructed from an appropriately flame retardant fabric.

3.6. It should be appreciated that any subsequent treatment to the
fabric, such as the use of colour dyes, may have an adverse effect
on its flammability performance and that in such circumstances the
required performance level will need to be restored.

3.7. Where the marquee is provided for the purpose of public
entertainment, and or for the purpose of a Licensed Premise, the
Licensing Authority, will require the production of a Certificate
showing compliance with one of the above Standards. ( see 3.2)

3.8. The marquee is to be erected by a competent person and must
not readily collapse when exposed to fire.

[Tom Sutton]

Thanks again Kurnal I would agree completely I also note

3.4. All unattached lining materials are to comply with British Standard 5867: Part 2, fabric type B, the specification for fabrics for curtains and drapes.
 
But as far as I understand they are not unattached they are stretched and attached to the metal structure below the roof canvas to hide the metalwork but I do not see how this wold make a difference to the flamability of the materials.