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Technical questions

 

TECHNICAL QUESTIONS

BUILT IN FIRE PROTECTION.

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The fire resistance of a component, such as a steel column, is its ability to resist the affects of fire for a period of time and this is usually measured by submitting the component to a fire test as defined in a nationally or internationally recognised standard.
Most construction materials have some natural resistance to fire and as such comprise built-in fire protection. This natural fire resistance may be enhanced by the use of added materials or systems that are known by the collective term of passive fire protection. For example the fire resistance of steel may be enhanced by the use of intumescent coatings, and concrete by sprayed cementitious coatings. While holes in partitions around penetrating services may be sealed by proprietary mortars or batts.
In a fire situations, the strength of structural steel will be reduced as the steel heats up. Ultimately, the steel will start to buckle and move when temperatures hits a critical point. In a steel framed building this will compromise its stability and compartmentation.
In the UK, third party certification bodies publish detailed certificates that outline the performance of fire resistant systems.
Because hot gases, fire and smoke will pass through thus spreading the fire and consequently the threat to life.                                          
The ASFP strongly advises building owners/users to ensure the routine maintenance of fire safety measures in buildings, arising from specific duties as defined in the Regulatory Reform (Fire Safety) Order 2005 – summarised in PowerPoint slides available elsewhere on this web site. There is no generic guidance available as maintenance will depend on the product sector, the working environment and service conditions; consult the fire protection manufacturer for advice for the maintenance of specific products. In the case of structural steelwork, if refurbishment or upgrading of the fire protection is required, the ASFP publication TGD 10 may be helpful.

RELIABLE INFORMATION.

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In the UK, third party certification bodies publish detailed certificates that outline the performance of fire resistant systems.
ASFP publishes a document entitled "Advisory Note 17" which is a position paper on assessments in lieu of fire testing which explains scenarios when a test cannot be conducted or when a test must be conducted and an assessment is not appropriate 
Yes the ASFP has a document, which was partly funded by the Department of Trade and Industry, entitled ‘Ensuring Best Practice for Passive Fire Protection in Buildings’ and this can be downloaded by going to the publication page. Click here  to see all of our publications.              

PRODUCT AND INSTALLER CERTIFICATION.

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Approved Document B (Fire Safety) to the England and Wales Building Regulations states Independent schemes of certification and accreditation of installers can provide confidence that the required level of performance for a system, product, component or structure can be achieved.
The following companies are known to provide such schemes:

STEEL AND REACTIVE COATINGS.

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In general, a minimum gap of 50  x dry film thickness of the reactive coating is recommended to allow adequate expansion in a fire, This guidance applies to the gap between the cladding and the flat surfaces of the protected steel section,  as well as the flange tips unless specific fire tests prove otherwise. Gap sizes may be reduced where manufacturers have specific fire test evidence. Continuous linear fixings [timber or metal] should be considered as part of the main beam, and duly protected from fire, unless other supporting fire test evidence can be provided.
No generic answer can be provided. Consult individual intumescent paint manufacturers for advice.
Guidance is given in Draft EN 13381-8 Reactive Coatings as follows:- Provided that one of the beams tested has a web depth of at least 600mm there will be no limitation on the maximum web depth that can be protected, otherwise the assessment will be limited to the maximum web depth tested plus 50%. The intumescent coating manufacturer should be asked to comment on any limitations or reinforcement.
Intumescent coatings are available for all types of service environments when used in conjunction with the correct topcoat system. However, there is no generic guidance available. Consult individual manufacturers for advice There are many ways of demonstrating durability of intumescent products. The obvious and most important is track record of real projects over many years. In addition some products have been tested to BS EN 16623. Underwriters Laboratory have a range of environmental testing requirements for both internal and external uses. Most recently the European Technical Approval Guidance for intumescents (EAD 350402-00-1106) also has specific durability testing depending on service conditions.                                         
As in the question above there are many standard aging test requirements in the national and European requirements previously mentioned. There is no generic guidance available. Consult individual manufacturers for advice.                                         
Some manufacturers have a range of fire test data where multiple topcoats have been applied prior to fire testing. It may be possible to overpaint certain intumescent coating systems. Consult individual manufacturers for advice.                     
Yes, in the case of cellular beams with circular or rectangular holes – Refer to the fire test protocol as detailed in Section 4 of the ASFP publication ‘Fire protection for structural steel in buildings’ – 5th Edition 2014. This publication can be downloaded from the publication page. In the case of cellular beams with other shaped apertures, refer to the manufacturer who must provide specific third party verification of the performance ‘Information is also provided in Advisory Note 11: the position on the fire protection of cellular beams protected with reactive coatings. This document can be downloaded from the ‘publications’ section of this website. Click here  to see all of our publications.     
Yes bolt heads should have the same resistance to fire exposure as the steel section, unless the fire protection manufacturer can demonstrate otherwise through third party verification of the performance.                                   
Generally this is not advisable unless the coating manufacturer has relevant fire test data.  The applicator MUST first consult the manufacturer of the coating system. It is likely  that the manufacturer will advise full removal of the top coat before re-application.     
Fire protected solid steel bars may behave differently from fire protected hollow steel sections in fire. The use of a specific protection system and its thickness should be based on a proven capability suitable to the application. In 2020, BS EN 13381-10 test method for determining the contribution for the fire resistance of structural members - applied protection to solid steel bars in tension was published.

STRUCTURAL STEEL FIRE PROTECTION.

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For a general overview please go to https://www.youtube.com/watch?v=P0fbd_Z_GVA&t=996s
You can use hollow sections in composite construction provided the manufacturer has undertaken a loaded hollow beam test for the appropriate fire resistance period and has had an assessment supported by a temperature analysis for the appropriate limiting temperature or a lower temperature. Where the concrete slab is formed with profiled metal floor decking, either the voids are filled, or the top flange is protected. As the top flange must be protected or the voids filled – no extra protection is required and the percentages in Table 20/21 of 5th edition of the Yellow Book are not applicable.

STEEL AND FIRE PROTECTION BOARDS OR SPRAYS.

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Definitely not. We do not advise mixing fire protection systems of any type unless there is specific test evidence available from the manufacturers concerned. Combinations of individual fire resistance periods are not additive in any circumstances, unless supported by relevant test information.
Fire protection board systems may be applied in a boxed or profiled configuration.

[1] For profiled board applications, Flexible boards such as those made from mineral wool may require cover strips at all joints. The use of rigid boards in this situation is generally not practical.

[2] For boxed board applications, The use of solid or “T-shaped “ noggings will usually be required on all beams with web depths of 533mm or greater. Contact the manufacturer for specific requirements. Flexible boards may require more internal support and cover strips at joints than rigid boards. Contact the manufacturer for specific requirements. Rigid boards are more self supporting but may require protection to the web joint or secondary support. Consult the manufacturer for specific requirements. Fire protection cementitious spray applications will require the use of retention mesh where the web depth between the flanges exceeds 650mm. Consult the manufacturer for fixing details. Note: mesh retention is also required where flange width exceeds 325mm.
Where a beam is passing through a compartment wall it should be fire protected to the appropriate level up to the wall and a fire seal should be utilised to prevent passage of fire through the compartment where the beam meets the wall. This fire seal should provide the necessary level of fire resistance, including fire integrity and insulation, and should be capable of dealing with any expected differential movement.
Where a beam or column forms part of a fire compartment wall there are two separate issues,
[a]  fire protection of the steel
[b] fire separation criteria for the wall.
The criteria for [b] may be the dominant feature, such that additional protection thickness/measures will then be required for the steel work in the region of the wall, in order to deal with the fire integrity and insulation requirement from Approved Document B – Appendix A.
Specifically, under normal circumstances, a maximum 140ºC rise in the average temperature of the surfaces on the non- fire side of the compartment wall will be permitted. This is to be contrasted with keeping steel temperatures below 500ºC or so to maintain the structural load-bearing capability of the steel.
In the case of non load-bearing walls consideration should be given to the deflection of the beam during fire and the effect that this may have on the integrity of the compartment wall.
Guidance on the fire protection of partially exposed steel members can be found in Section 1.63. ASFP publication “Fire protection for structural steel in buildings. 5th Edition”.  Click here to see all of our publications.     
Where brackets, angles and other secondary fixings are to be attached to a steel beam, or column, the passage of heat into the structural steel via these fixings must be kept to a minimum. In order to achieve this fire protection of the fixing may be required. Consult the fire protection system manufacturer for specific details.
Where fixings are installed prior to the fire protection:
1) Boards can be cut to fit around them.
2) In the case of cementitious sprays, the fixings should be masked and then the spray may be applied in the normal way and the masking removed afterwards to reveal the fixings.
If fixings are installed after the fire protection system then areas of fire protection, of a minimum size, can be cut away to allow the fixings to be attached. A patch repair may be required in some circumstances to reinstate the required level of fire resistance.
Contact the fire protection system manufacturer for specific requirements and procedures.
The limits of deflection are described in the guidance provided in Approved Document B 2019 including 2020 amendments volume 1 – section 7.14, in support of the UK  Building Regulations.
This guidance will limit the steel deflection and allow the partition supplier to provide an interface detail.                               
Gypsum based products are generally less chemically aggressive than those based on cement.
Where cement based products are applied to primed steel, an epoxy type primer will generally be compatible whereas an alkyd based primer will not be compatible.
Cementitious sprays are often applied to bare steel.
It is essential that installers and the designer consult with the cementitious spray manufacturer to confirm the compatibility of any steel priming system.                                         
Where timber joists are located into the web of a beam the steel beam will usually need protection from fire in order to comply with the requirements of Approved Document B Appendix A. The timber joists which penetrate through the fire protecting layer must be fire stopped with a tested method or appropriately fire tested penetration seal. Consult manufacturer for specific guidance.
In addition, the timber floor will need to be fire resisting to the appropriate level and fire protection to the timber floor and timber joists may be required. The methods used to fix any fire protection system to the timber shall be as tested in a relevant fire test.
The fire protection of concrete slabs will depend on [a] the construction, density, the thickness, the thickness of concrete over reinforcement steel, the fire resistance requirements for the concrete floor slab, and [b] the thermal requirements arising from the location of the slab in the building. Consult the manufacturer for specific guidance.                                   
The fire resistance requirements of the wall may change according to the requirements of Building Regulations Approved Document B 2019 inc 2020 amendments, and particularly where the building wall is less than 1 metre from the boundary of the property.
The requirements for the fire resistance criteria of the boundary wall must be ascertained in order to assess any additional requirements for the structural steel associated with the boundary wall.
Consult the manufacturer for specific guidance                                            
See Advisory Note 21 Fire protection of secondary steelwork.Click here  to see all of our publications.     

ROOFS.

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See Advisory Note 20 protection of roof components of portal framed buildings.Click here to see all of our publications.             

CONCRETE FLOORS.

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Yes see TGN 1 Spray Coatings for fire protection of concrete floors. Click here to see all of our publications.               

CAST AND WROUGHT IRON.

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ASFP are of the opinion that data obtained from mild steel fire tests can be used to provide protection thicknesses for cast iron and wrought iron using the same limiting temperatures, subject to the conditions referenced in the following reports [a] and/or [b]
[a] BCIRA Report ‘Cast iron in building structures – revived interest in a proven case’ by E.R.Evans dated November 1984. Further information can be obtained from:- Castings Technology International, Advanced Manufacturing Park, Brunel Way, Rotherham S60 5WG. T: +44 (0)114 254 1144, E: info@castingstechnology.com
[b] ‘ Historic buildings and fire performance of cast iron structural elements’  by J R Barnfield & A M Porter
NOTE that the Structural Engineer must establish the Section Factors and be satisfied with the integrity of the iron work before specifing fire protection.                         

FIRE RESISTING DUCTS.

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Any oversized gap shall be reduced in size such that the additional fire penetration seal around the duct can function as fire tested within a maximum residual opening.
Responsibility for the satisfactory performance of each element of building construction (e.g. walls, floors, cavity barriers, etc.) lies with the installer of each particular element. The ‘change over’ of responsibility occurs at the interface between the fire resisting ductwork and the elements. It is imperative that the interface detail does not compromise the fire performance of either the element of building construction or the fire rated duct. The building designer, mechanical services designer and the installer all have a responsibility to pay ‘due care’ to this detail.
Further details are provided in ASFP ‘Blue Book’ publication ‘Fire resisting ductwork'. Click here  to see all of our publications.     
In general the answer is no, especially in the case of ductwork used for smoke extraction.
Any such mounting is likely to compromise another essential function of the ductwork system, where it passes through a fire resisting element of constructions, unless other proven measures have been incorporated to mitigate such an effect.
Ordinarily, contact the installation contractor and confirm that there has been relevant fire testing and competent assessment on the system. If there is no satisfaction then contact the main contractor/employer/CDM Coordinator to raise any concerns. Ultimately contact the local enforcing authority.
Approved Document B, Volume 1 Section 17 or Volume 2 Section 19, summarises the legal duties on contractors arising under Regulation 38 to ensure that users of building [responsible persons] can make a relevant risk assessment as required under the Regulatory Reform (Fire Safety) Order 2005.  Observers have a Duty of Care.
When the specification is for a prescribed period of fire resistance then all fire resistance criteria shall apply, in terms of the load-bearing capacity (stability), integrity and insulation criteria. Removal of the insulation criteria shall only apply in exceptional circumstances.
It is a requirement that where these compartment walls/floors are penetrated by ducts or other building services, the fire performance criteria for the penetrated wall or floor are maintained, such that fire in one compartment may not spread to other areas.
In specific installations, Building Control authorities may waive the insulation requirement or allow a reduced period of insulation, Examples include some car parks, where enforcers have considered that there was not a possibility of combustible materials being in close proximity of the ductwork.
The supports used must be as fire tested in the ductwork system. Because of the way duct supports are fixed or anchored in fire tests, alternative fixings are permitted provided that suitable test evidence is available to justify the use on the intended duct system.
Further information is available in ASFP ‘Blue Book’ publication ‘Fire resisting ductwork'. Click here  to see all of our publications.                                                                     
The answer comes in two parts. DIAP and EXAP rules are an output from European harmonization of fire testing methods and classifications. At a national level, experienced persons or fire test organisations have previously provided assessments of expected performance based on expert judgement.
[a] The direct field of application (DIAP)
DIAP rules are provided in BS EN 1366 test standards. They are derived from information obtained from tests carried out in accordance with relevant EN 1366 tests at recognised laboratories in Europe.  The test results achieved by a particular design may be directly applied to a limited number of variations (e.g. a reduction in duct size) without recourse to expert advice, providing the design remains substantially as tested.
The scope of the current BS 476 test method does not consider the effect, detrimental or not, that variations in the test construction may have on the achieved performance of the duct.  The test result only applies to the tested design and size; the field of direct application is very limited. The ASFP ‘Blue Book’ publication ‘Fire Resisting ductwork'. Click here to see all of our publications. 
[b] The extended field of application (EXAP) rules are derived from test evidence to relevant BS EN 1366 test standards and is provided in the relevant section of BS EN 15882. EXAPs shall be based on primary test evidence to BS EN 1366 and may be supplemented by appropriate test evidence generated from other sources, or other relevant historical data. See Technical Guidance document 20 for more information.  Click here  to see all of our publications.
The EXAP rules consider changes in the tested design beyond the scope of direct application and may also consider variations to the tested design.  For example, an increase in duct size which necessitates the inclusion of a joint in the duct walls.
At a national level, for the purpose of assessments for the extended field of application, laboratories accredited by UKAS for conducting the relevant tests might be expected to have the necessary expertise or competent authority/persons appropriate to the complexity of the evaluation undertaken.                                   
Access panels are frequently fitted to fire resisting ductwork for purposes such as cleaning or access to dampers.  The panels are fitted in the walls of the duct but must not interrupt the duct structure, e.g cross joints, stiffeners and supports.  Ideally the access panel will have been tested as part of the fire resisting ductwork system.  The test must have demonstrated that the design of access panel is able to maintain the required fire performance requirements of the ductwork system without weakening the structure of the duct.  The maximum size of panel is that tested.
Proprietary access panel systems are available.  To be acceptable for use as part of a ductwork system they must have been shown by test to be capable of maintaining the required fire performance requirements of the ductwork system when mounted in a similar type of duct.  The access panel assembly includes the panel, the mounting frame, the fixings holding the panel in the frame, the fixings fastening the mounting frame to the duct and any seals.                                      
[a] A test result for fire resisting horizontal ducts is applicable to horizontal ducts only.
[b] A test result obtained for fire resisting vertical ducts is applicable to vertical ducts without a horizontal branch.
[c] However, for fire outside ducts, if a test is successfully made on a horizontal duct with a branch, for a stated period of fire resistance, then vertical ducts may include a horizontal branch for that same period of fire resistance.
[d] For a rectangular duct, the maximum aspect ratio between the longer and shorter sides is 4:1.
The answers are different for those ducts tested to BS 476 Part 24 or tested to BS EN 1366 test methods.
In the case of BS 476 Part 24 test data, circular and flat oval straight seamed and spirally wound steel ducts may be assessed on the basis of the tests on rectangular ducts. Details of the construction of circular and flat oval, straight seamed and spirally wound steel ducts must be provided by the duct manufacturer. Further details are provided in ASFP ‘Blue Book’ publication ‘Fire resisting ductwork'.  Click here to see all of our publications.
In the case of BS EN 1366 test data, no equivalence is permitted and all ductwork systems must be individually tested. The published European DIAP and EXAP rules apply.
As the vast majority of fire tests on ducts are conducted with rigid ducts it is not appropriate to extrapolate this data for flexible ducts. Therefore, unless the flexible duct system has been fire tested, the guidance cannot be assumed to apply.                      
Yes. Fire dampers, without a smoke leakage classification, are not designed to protect against smoke which is a concern for protected escape routes. Such a closed fire damper will still leak a considerable quantity of smoke. Fire dampers will not prevent heat conduction and radiation from distorting ductwork in the escape route and causing joints to open up and contaminate the escape route.
Therefore the ductwork itself would need to be fire resisting (tested to BS 476: Part 24 or EN1366-1 with fire exposure from the inside) and not serve the protected route. Alternatively, it needs to be enclosed within fire resisting construction e.g. a suspended ceiling tested from above which must be smoke tight.
However, an alternative would be to use ‘dampers’ and not protect the duct – this is possible but the dampers would need to be ES classified leakage rated fire dampers. Such dampers should achieve an ES classification to BS EN 13501-3 when tested to BS EN 1366-2. These dampers are considered to have good smoke resisting properties in addition to fire resistance. Dampers tested to BS 476 cannot provide an ES classification.
For situations where ductwork serves a dwelling house or internal parts of a flat see FAQ 5 below Source: Approved Document B 2019, incorporating 2020 amendments, Vol. 2; clause 10.15 or Vol 1; Clause 9.16. Further details are provided in ASFP ‘Blue Book’ publication ‘Fire resisting ductwork'. Click here  to see all of our publications.

 

No. Ductwork passing through a protected corridor should be fire resisting when tested to BS 476: Part 24 or EN1366-1 (with fire exposure from the inside) and not serve the protected route for the required fire time. We have not seen any result which indicates that an ordinary steel duct would survive such a test.
DW 144 is a specification for ventilation ductwork, not for fire resisting ductwork. Only ducts tested to BS 476: part 24 or EN 1366-1 can provide fire resistance.
An alternative to using a fire resisting duct would be to use ES classified leakage rated fire dampers. Such dampers should achieve an ES classification to BS EN 13501-3 when tested to BS EN 1366-2.
Source: Approved Document B 2019, incorporating 2020 amendments, Vol. 2; clause 10.6 or Vol 1; Clause 9.6. Further details are provided in ASFP ‘Blue Book’ publication ‘Fire resisting ductwork'.  Click here  to see all of our publications.              
We are not aware of any publicly available test evidence to confirm a generic solution. However, there are proprietary manufacturer’s systems that have been tested using this approach. Any such system would need to specify the ductwork construction, fixtures and fittings, method of support etc as well as the details of the specific mineral wool. It would also need to be supported by appropriate test evidence.                  
No. class 0 (or European Class B-s3, d2 or better) does not refer to fire resistance of the duct but to how the surface of the duct, or any material applied to it, ‘reacts to fire’ i.e. if the surface material if ignited, spread flame over its surface or has a high heat release.      

FIRE STOPPING APPLICATIONS.

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Manufacturer’s marketing information may not always include information for a particular field of application. The suitability of use is best justified by the manufacturer, by:-
The production of a valid fire test or assessment report against the requirements of a European fire classification report to EN 13501-2 (when tested to EN 1366 Parts 3 or 4 as appropriate) as issued by a UKAS accredited fire test laboratory or in the case of an assessment by a competent person or body, which should adequately demonstrate the suitability of a fire stopping product for use within a specific application or a range of applications.
See ASFP ‘Red Book' publication 'Fire stopping'.  Click here to see all of our publications.    
Yes, Approved Document B states: “The performance of a fire-separating element should not be impaired. Every joint, imperfect fit and opening for services should be sealed. Fire-stopping delays the spread of fire and, generally, the spread of smoke as well”.
Also see ASFP ‘Red Book' publication 'Fire stopping'.  Click here to see all of our publications.     
Any system intended to be used as a pattress cover to the void behind must be proven by fire test or assessment for the intended field of application and for the required fire resistance period. Ad hoc patching will not meet all the fire resistance criteria required.
Under these circumstances it will be impractical to achieve an adequate fire stop with any of the common pipe closure solutions, but this does not remove the requirement to provide such a fire stop. It will therefore be necessary to either:-
[a] reposition/extend the pipe such that a pipe collar can be fitted to the soffit of the floor or
[b] use a smaller diameter pipe so that a collar/wrap/sleeve can be fitted within the floor, or
[c] re-drill the hole in the floor, so that a collar/wrap/sleeve can be fitted within the floor, or
[d] the pipe could be boxed in by fire resisting construction, or
[e] more innovative pipe closure devices, specifically designed and tested to cope with this situation, would be required.
The law requires that a relevant fire risk assessment is made and maintained to identify all potential hazards and associated risks throughout the life and use of the building, and that all actions taken are recorded. The fire resistance and or other provisions should be enhanced in accordance with regulatory requirements to reduce risks to an acceptable level. The methods used can only be determined in relation to the particular problem.                                      
We refer you to ASFP Red Book and 3rd party certificated data sheets for the appropriate application. The required performance and guidance on quantity shall be confirmed with the manufacturer, and installer, of the selected product. Click here to see all of our publications.                                  
The simple answer is no. While it may be tempting to use e.g. manufacturer A’s mineral fibre batt with manufacturer B’s adhesive, the combination is unlikely to have been tested and therefore may not perform in fire as intended. See Advisory Note 6.  Click here  to see all of our publications.                                         
In the absence of test evidence, the default answer is again no. While it may be possible to get an assessment from a fire consultant or test/certification body to cover such an application, such an installation may not be covered by any of the manufacturers’ warranties or after sales service.
The ASFP strongly recommends the use of third party certificated products. Such products will have a scope of application which will cover their use with other compatible components which may include products from other manufacturers. See Advisory Note 6. Click here  to see all of our publications.
1. This is dealt with in technical guidance to building regulations as follows:
England & Wales, Approved Document B, Section 9 of vol. 1 for dwellinghouses, and section 10 of vol. 2, for buildings other than dwellinghouses.
Scotland Technical Handbook, Fire Domestic 2019, clause, 2.2.9 Openings and service penetrations, and Scotland Technical Handbook, Fire Non Domestic 2010, clause, 2.1.14 Openings and service penetrations
Northern Ireland Technical Booklet E 2005, clauses 4.43 and 4.45 to 7.
2. The guidance requires that pipes passing through a fire-separating element should either be provided with a proprietary sealing system (such as an intumescent pipe collar or wrap), or be sleeved with a non-combustible pipe for at least 1m each side of the separating structure.
3. The guidance does give a third option but only for uPVC stack and branch pipes passing through compartment walls or floors in flats or when a branch pipe penetrates a wall separating dwellinghouses. In this case the stack and branch pipes must be no greater than 160mm and 110mm nominal internal diameter respectively, and form an above-ground drainage or water supply system only.
4. In the third option referred to above, the guidance states that the pipes must be located within  an enclosure which has a fire resistance of 30 minutes (integrity only) when exposed to fire from outside the enclosure. There are restrictions given on the types of materials that can be used to form the enclosure and the location of access panels. Gaps around the pipes should be as small as possible and still need to be fire-stopped where the pipes pass through the floor and the pipe enclosure.
5. It must be borne in mind that the guidance to the building regulations has been written assuming that installations, including the pipe enclosures and fire-stopping, have been fitted with good workmanship, are not damaged during the life of the building, and that every aspect of the guidance has been followed. The ASFP consider that all these conditions are unlikely to be met in practice. Therefore we strongly recommend that suitable pipe closing devices, e.g. tested intumescent pipe collars and/or wraps, are used at the penetration through the floor to prevent fire penetrating the floor. Similarly, the ASFP strongly recommend that fire tested pipe closing devices are also fitted around uPVC branch pipes that penetrate walls separating dwellinghouses.
6. Where pipe collars or wraps are used, care should be taken that any remaining gaps are fire-stopped with a suitably tested system that is compatible with the particular pipe collar or wrap that is being used.

See ASFP ‘Red Book' publication 'Fire stopping' and Advisory Note 2. Click here  to see all of our publications.