Presentation by Nigel Blacklock at the Single Ply Roofing Association Conference 2019 at Heythrop Park, Oxfordshire. More information:https://spra.co.uk/events/spra-awards-2019-live-blog/

1. Fire – Flat Roofs
SPRA Conference Variant
Nigel Blacklock – Technical Director

2. Warm - Up
Definitions
Flammable - Easily set on fire
Inflammable - Easily set on fire
Combustible - Able to catch fire and burn
Non - Combustible - Does not burn
Incombustible - Does not burn
Wall – Structure that defines an area, carries a load or provides
shelter
Roof – Structure forming the upper covering of a building (0-70°)

3. • Came into effect April 2007,
amended in 2010 and last in 2013
• Volume 1 – Dwellinghouses
• Volume 2 – Buildings other than
Dwellinghouses
• Building Bulletin 100 – Design for
fire safety in school (copies most
of Approved Document B Vol 2)
Approved Document B Fire Safety 2006

4. B1 – Means of warning and escape
B2 – Internal fire spread (linings)
B3 – Internal fire spread (structure)
B4 – External fire spread
B5 – Access and facilities for the fire services
Appendices
Approved Document B Vol 2 -
England
Focus is on saving life, not property

5. B1 – Warning and Escape
“ A flat roof forming part of and means of escape should
……provide minimum 30mins fire resistance.” (Appendix A
Table 1)
Approved Document B –
references to Roofing
B2 – Internal Fire Spread (Fabric)
Only mention relates to internal surface of a rooflight, but
relevant where the roof deck is the ceiling.

6. B3 – Internal Fire Spread (Structure)
B3iii – “Elements of Structure”
“Roofs, unless they serve the function of a floor, are not treated
as elements of structure.”
Therefore, roofing requires mainly to comply to B4 – External
Spread except if it is a fire escape or serves as a floor (e.g. a
roof terrace)
Or
Approved Document B –
references to Roofing

7. B3 – Internal Fire Spread (Structure) cont’d
If there is a junction with a compartment wall and the underside
of the roof.
Here the roof deck should be of “limited combustibility” (means
concrete and steel – timber OK if <15m high) and the roof
covering to “unrestricted” classification. The wall taken to the
underside of the deck and sealed with a cement mortar or the
compartment wall can extend 200mm above the finished roof
surface (500mm in BB100).
Approved Document B –
references to Roofing

8. B4 – External Fire Spread
“Risk from an external fire source with flame spreading or fire
penetration of the roof and in each case fire spreading from
building to a building beyond the boundary or vice-versa.”
Approved Document B –
references to Roofing

9. Preliminary (BS476-3 + TS1187 Test 4)
Test Flame (Brand) for 1 min – Fixed
End = No flaming or no ignition
Testing for External Fire Exposure
to Roofs
Spread (BS476-3 only)
Radiant heat and Brand for 3 mins
End = No flaming or no ignition
Penetration (BS476-3 + TS1187 Test4)
Radiant heat and wind, after 5 mins
Brand for 1 min – Moving
End = After 1 hour

10. National
Test and classification to BS476-3:2004
Classification of Fire Performance
First letter – Fire Penetration Classification
• A - Those specimens which have not been penetrated within 1 hour
• B - Those specimens which are penetrated in not less than 30 minutes
• C - Those specimens which are penetrated in less than 30 minutes
• D - Those specimens which are penetrated in the preliminary flame test
Second letter – Spread of Flame Classification
• A - Those specimens on which there is no spread of flame
• B - Those specimens on which there is not more than 530mm, spread of flame
• C - Those specimens on which there is more than 530mm, spread of flame
• D - Those specimens which continue to burn for 5 minutes after the removal
of the test flame or with spread of flame more than 381mm, in the preliminary
test

11. European
Test to TS1187 (t1 Germany, t2 Scandinavia, t3 France & t4 UK)
Classification to BSEN13501 – 5 : 2004
TS1187 t1, t2 and t3 test results are not valid in the UK
Classification of Fire Performance
Test 4 differs from BS476-3 in that only a Preliminary Spread of
Flame test is required and the Fire Penetration test. It provides
one classification letter.
So provided a test sample is not penetrated within 1 hour and it
does not continue to burn for 5 minutes after removal of the test
flame or with spread of flame more than 381mm, in the
preliminary test it will achieve Broof (t4).

12. Limitations on Roof Coverings
Summary of Table 16 from AD B with addition of Technical Handbook (Scotland)
summary
National
Class
European
Class
Minimum Distance from
Any Point on Relevant
Boundary - England
Minimum Distance from
Any Point on Relevant
Boundary - Scotland
AA, AB or AC Broof(t4) “Unrestricted” and can be
used anywhere on
"Low Vulnerability" (<6m)
BA, BB or BC Croof(t4) At least 6m of the
boundary
"Medium Vulnerability" (6-
24m)
CA, CB or CC Droof(t4) At least 6, 12 or 20m of
the boundary depending
on the building type and
use
"Medium Vulnerability" (6-
24m)
AD, BD or CD Eroof(t4) At least 6, 12 or 20m of
the boundary depending
on the building type and
use
"High Vulnerability" (>24m)
DA, DB, DC or
DD
Froof(t4) At least 20m of the
boundary depending on
the building type and use
"High Vulnerability" (>24m)

13. European Commission Directive 2000/553/EC
Lists build-ups that achieve Broof “without the need for testing.”
Classification Without Further
Testing (CWFT)
Products intended to be
fully covered in normal
usage by:
1. Loose laid gravel with a thickness
of at least 50mm or a mass ≥
80kg/m² (aggregate size 4-32mm)
2. Sand/cement screed min 30mm
thick
3. Stone or concrete slabs min 40mm
thick

14. National designations of RBM roof build-ups that are deemed to
be of designation Broof (t4):
• Bitumen-bedded stone chippings to whole surface min
12.5mm depth.
• Bitumen-bedded tiles of non-combustible material.
• Sand and cement screed.
• Macadam.
Approved Document B –
Appendix A Table A5

15. • Growing Medium should be certified for use on Green Roofs
and where no permanent irrigation organic content should be
<20% and peat free.
Green Roofs – GRO Design Guidance
• Fire Breaks should be 50mm thick 20-40mm rounded pebble
or paving slabs around all perimeters and glazing, ideally
500mm wide, with a 1m wide break every 40m.
• Maintenance is important to prevent vegetation growing over
Fire Breaks and to remove wildflower dry thatch in the Autumn.

16. A1 - Rockwool & Foamglas (unfaced)
D - Wood, PIR
E - PIR, EPS, XPS
F - Not Tested
• B to F are combustible giving off varying degrees of smoke
and/or burning droplets
Euroclass Reaction to Fire (Fire Growth)

17. Many building products are combustible and yet when used in a
system approach will meet the highest requirements of AD B.
Often the same classification is achieved for comparable build-
ups where one has combustible insulation and the other has
non-combustible insulation.
Euroclass E products can be used in a system approved
without the need for further testing (this is yet to be confirmed
by the Ministry of Housing Communities and Local Government
(MHCLG) for roof terraces on Residential buildings above 18m).
System Philosophy

18. They are interested in preventing loss of life
and
Total loss of property
AD B acknowledges this consideration, but does not make extra
requirements
Therefore, some Insurers are seeking more
The Insurers

19. They often seek roof systems that exhibit no spread of flame.
Some will accept a Factory Mutual approved Assembly.
The Insurers

20. Challenges:
• Only 2 test houses that
can do UK fire test (only
one in the UK).
• No EXAP rules for
testing – so less
common build-ups not
tested.
• A cap-sheet with no
spread of flame will
compromise other
product or system
characteristics.
Roofing Industry Fire Test Issues

21. • At the end of 2018 the Government amended AD B-Fire to
cover non-combustible cladding and whilst it clearly states
the limits of this change excludes roofing, there are grey
areas.
Changes to Approved Document B Fire
• ‘Specified Attachments’ refer to a balcony, does that mean a
roof terrace?
• Is a parapet to be included in the guidance?
• Roofing systems are commonly turned up walls by 150mm
and greater – what restrictions, if any, are there now?
• The Construction Industry eagerly awaits clarification!

22. Thank you