FIRE DOORS RHUL REQUIREMENTS

Transcription

1 Fire Safety Technical Guide FIRE DOORS RHUL REQUIREMENTS This guide draws together the general requirements of a range of published standards and reference documents and is to be used in addition to any other requirements from the Local Fire or Building Control Authority/Approved Inspector. Its purpose is to ensure that the College operates a consistent approach to fire safety. Where any doubt exists as to the action to be taken, or advice or assistance is required, contact should be made with the College Fire Safety Officer. 1 FIRE DOORS (FUNCTION AND STANDARDS) 1.1 Function Fire doors are required to perform two main functions; a) To maintain any compartmentation of a building, which has been introduced to limit the size and spread of fire in order to control the perceived risk (this will include areas of high fire risk such as Plant Rooms, Kitchens, Service Ducts, Workshops etc); b) To allow access to protected escape routes, both vertically and horizontally, without any loss of fire resistance, and limit smoke movement in the structure forming these routes, (this will include Protected Corridors, Staircases, Lobbies, Shafts, Dead-end escape areas etc) In addition, all doors to sleeping accommodation will be Fire Doors. 1.2 Standards and Guidance Reference documents Reference is made here to BS Code of Practice for Fire Door Assemblies, which makes recommendations regarding the significant parameters governing the design and use of fire door and frame sets. The rating for a fire door is derived from its performance when tested in accordance with BS (or BS EN ) and is judged by the time it takes to fail for both integrity and insulation. However, regulatory guidance will only refer to a door s performance for 1

2 integrity, hence the designation FD30 for a door able to resist failure for 30 minutes. A fire strategy might require a door to also meet the criteria for insulation, in which case the designation will be FD30/30. Certain doors are also required to restrict the spread of ambient (cold) smoke and will be identified by the suffix S, having been tested in accordance with BS (or BS EN ). The guidance on where a fire door will be required and what rating it should have is given in: a) Approved Document B (often simply known as ADB) of the Building Regulations or; b) BS Code of practice for fire safety in the design, management and use of buildings - where a risk-based approach is adopted; or c) BS Application of fire safety engineering principles to the design of buildings for fire engineered strategies Design standards and documentation The following paragraph, taken from BS8214, forms an essential part of the process of project management for new buildings or extensions to existing buildings. It should also be followed when an alteration or addition is made to an existing building, which involves the installation of a new fire door. The building designer should ensure that all fire doors to be used are of a design that has been tested or assessed for the required fire resistance period, and that documentary evidence exists to that effect. Where the elements of a fire door are to be obtained from different sources, the building designer should ensure that the elements to be used are compatible and are able to provide the required fire resistance period, and that documentary evidence exists to that effect. Before proceeding with contractual commitments it should be established that evidence of performance exists which meets with the approval of the enforcing authority. Project Managers must be aware that the provision of the correct documentary evidence plays a vital role in supporting the Fire Risk Assessment of a building, as the College must be able to produce such evidence when requested by the Fire Authority. Any person, who is required to install a fire door (with or without frame), must produce documentary evidence to support the rating and performance of that door and/or frame Installation Doors and Frames The failure of doors under fire conditions usually occurs either at the gap between the door and the frame, or at one or more of the points where building hardware is fixed (particularly at the hinges or lock positions) or, in the case of glazed doors, at the line of the junction between the glazed area and the rest of the door. For this and other reasons, it is particularly important to ensure that doors installed on site conform, in dimensions and workmanship, to the manufacturer s specification for the appropriate fire resistance test report/assessment. 2

3 Doors should be hung to give an equal gap across the head and down both jambs. A typical gap to achieve good fire performance is between 2 mm and 4 mm. Certain smoke seals might require a larger gap in order to operate without causing significant frictional increases, but the gap should remain within tested tolerances. The selection and installation of door frames is as important as the door itself. Ideally the two should be matched and supplied as a complete unit, as the fire resistance of one may depend on the design features of the other. In order to maintain the fire resistance of a fire-resisting wall or partition, and the frame of a door assembly, the joint between the two elements should be adequately sealed. Tables 2 and 3 of BS provide recommendations on tolerances and infilling of this joint. Doors should be hung to ensure a good fit to the frame when closed and the junction between door assembly and surrounding structure should be adequately sealed. Care needs to be taken when adding smoke seals as these can inhibit the complete closing of the door if not fitted correctly. HINGES Unless otherwise specified by the Manufacturer, a Fire Door will be hung on a minimum of THREE metal hinges with a melting point of not less than 800 C 2 FIRE DOORS (GENERAL) 2.1 Direction of escape Any door forming part of an escape route should open in the direction of escape travel. This is an absolute requirement if the number of people expected to use it exceeds 60. If that door is also a Fire Door, it should be rebated into a frame and have the required intumescent and smoke seals. It should not be a double swing door unless it is a mid-corridor smoke check door, which may be double-swing but must be fitted with smoke seals. 2.2 Intumescent Materials and Smoke Seals Door edges are the part of a door-set most susceptible to penetration by heat and smoke because the pressure of a developing fire drives hot gases between the door and frame, leading to loss of integrity. This used to be countered by the use of a large (25mm) doorstop, but this relied heavily on a very close fit between the door and frame. The modern solution is to use a strip of intumescent material, set into either the door edges or the frame opposite the edges. At around 100 C this will expand to fill the gap between the door and the frame, thus maintaining its integrity. Several points must be considered in their use: If a door has achieved a rating when tested with intumescent materials, then it must be supplied complete with them There are several different types, so the correct type, as specified by the manufacturer of the door-set, must be used. Different types are not interchangeable. 3

4 They may be fitted either in the door frame or the door edges. They must be applied to both vertical edges and the top; they are not required along the bottom edge Where a door is also required to have smoke seals the best solution is to use a combined strip. The Brush type is preferred to the rubber blade type as experience has shown that they are longer lasting. At no time are these strips to be overpainted as this causes them to harden and lose their ability to perform When fitting strips and seals they must not be altered in shape or size, as this will reduce their effectiveness On doors up to FD30 rating it is acceptable to interrupt the strip for hinges or latches On doors over FD30 rating, where double strips are required, one may be interrupted but the other must be continuous When these strips are used, it is no longer necessary to provide an oversized doorstop. A standard 12mm planted stop is acceptable Concealed Intumescent - Several manufacturers offer door assemblies in which pressureforming intumescent material is concealed behind the timber lipping of the door leaf. In such cases, the manufacturer s documentation must be provided and no attempt is to be made to plane the edges of these doors or route them to apply further seals. If smoke seals are also required, they must be fitted to the door frame. 2.3 Self-Closing Devices Fire doors can only operate correctly if they are fully closed at the time of fire. It is, therefore, normally necessary for them to be fitted with a self-closing device. A Fire door, except to a cupboard or service duct (both of which are normally kept locked shut), should be fitted with a self-closing device (other than rising-butt hinges) that should: a) be of a type that cannot readily be disconnected or immobilized and does not embody a mechanical hold-open facility unless it automatically releases the door in a fire situation; and b) override any latches fitted to the door or, in the absence of a suitable latch or other positive device for holding the door shut in its frame, be of a type that, when tested in accordance with BS or BS or BS EN , is shown to be able to hold the door closed in the frame for a sufficient period of time for the closing role to be taken over by a thermally activated sealing device (e.g. an intumescent seal), or throughout the full period of exposure if such seals are not incorporated; and c) conform to BS EN The strength and control of the closing device should be compatible with the size of the door, and any other factors, such as resistance from latches and air pressure, heavy traffic use, abusive treatment, use by disabled persons. Perko style closers are not normally acceptable (RHUL Fire Safety Officer must be consulted if no other option is practicable) 4

5 2.4 Air Transfer Grilles Where a fire door is required to be fitted with an air transfer grille, it should only be fitted with one that is capable of sealing both by thermal initiation and by interface with smoke sensors either directly or via a fire alarm panel. Mechanical fire-resisting air transfer grilles are closed by the activation of a thermal release mechanism usually preset to operate between 70 C and 74 C. The majority of fire doors now require smoke control and consequently any fire-resisting air transfer grille fitted should also be able to seal automatically when activated by interface with smoke sensors or a fire alarm panel. The installation of air transfer grilles should only be undertaken when full fitting instructions and relevant wiring diagrams are available, and should only be undertaken by competent persons. In the case of electrically interactive air transfer grilles, the installer should liaise with the persons responsible for the fire alarm panel or building management system. All air transfer grilles should be installed in accordance with the manufacturer s installation and commissioning instructions. 2.5 Hardware Building hardware falls into two categories: essential and non-essential. The selection of building hardware is vital to the performance of fire-resisting doors and it should be selected and fitted with care in accordance with the manufacturer s instructions. Essential hardware Items vital to the fire resisting performance of the door, which would include Hinges/Pivots, a Latch and a Self-Closing Device. Non-essential hardware Items not vital for fire-resistance but might be vital for means of escape or general fire performance, including Handles, Automatic Release Mechanisms, and Push Bars. All door furniture should be fitted in such a way as to ensure that the fire-resisting properties of the doorset are not compromised. It is recommended in most instances that building hardware be bedded in intumescent mastic or pre-shaped intumescent pads to restrict heat transfer to the door edge via the metal products. Interruption of intumescent seals at the positions of building hardware should be avoided where possible. Locks and Latches Any door forming part of an escape route should open in the direction of escape travel. This is an absolute requirement if the number of people expected to use it exceeds 60. It should be easily and readily openable without the need for a key or other separate device. If a Security Risk Assessment has recommended that the door be locked, then that lock must be easily overcome by a single action lever type handle or other opening device. If the door 5

6 is fitted with an Electromagnetic type locking device it must comply with the requirements of BS :2007, the significant elements of which require that: a) the lock defaults to the open position in the event of any power failure or short circuit b) the lock opens on actuation of the fire alarm system c) the lock is provided with a manual override (green box break glass) adjacent to the door. Disability Considerations Locking devices associated with Thumb turns should be avoided. It should be possible to operate all door-opening furniture one-handed, without the need to grasp or twist. Care should be taken in the selection of security and fire exit fittings, such as short lever turn buttons, bolts, latches or locks, with the aim of making them manageable for all users. Wherever possible, door opening furniture used in conjunction with locks and latches should have a lever action. Knobs with a spherical, circular or similar design, as well as small symmetrical turn buttons, are difficult to use by people with limited dexterity, arthritis or a weak grip. 2.6 Glazing Vision Panels In general, a vision panel should be provided in any door in an escape route, circulation route, corridor, stair enclosure, lobby etc. and in any double-swing door. Additionally, a vision panel should be provided in: a) a door to an Inner Room, where fire detection is not provided in the Access Room b) in doors to laboratories, kitchens and similar areas where hazardous items are regularly carried through the doors Where a vision panel is provided to comply with Disability Access requirements, Approved Document Part M of the Building Regulations must be consulted. Where the need for privacy or technical reasons is paramount, a vision panel may be omitted, provided a suitable fire risk assessment is carried out Fire-resisting glazing Fire-resisting glazing is categorised in two performance criteria as tested in accordance with BS or BS EN : Integrity is able to resist the passage of fire, heat and smoke by remaining intact for a specified period Insulation is able (in addition to the integrity performance) to resist the transfer of heat through the glass so that the non-fire side remains cool. 6

7 Restrictions apply to the use of non-insulating fire-resisting glazed elements because of the risks that they pose from their relative inability to afford adequate protection against transmitted heat. In this respect there are four possible hazards to consider, even if the integrity of the glazed element as a flame and smoke barrier is maintained. These are: Direct exposure to potentially high levels of radiant heat with the risk of burns to exposed skin; Convective heating of the atmosphere in the escape way; Smouldering smoke generation (before ignition) from floor coverings, fixtures and fittings in the corridor; Secondary ignition and flaming of fixtures and fittings in the escape way. The limitations on the use of Non-insulating glazing are shown in BS9999 (table 29) and ADB. Glazing able to provide insulation properties may be used without any restrictions. There are many products on the market which go by a variety of trade names. Those which provide Integrity only are: Pyrostem; Pyroshield; Firelite; Keralite; Vertroflam; Pyroswiss; Pyrocet; Pyrosec; Tempaflam; Fireswiss; Pyroguard; Pyrobelite; Pyrodur; Contraflam; Pyran. (other products may be available) Those which provide both Integrity and Insulation are: Pyrobel; Pyrostop; System Glass; Pyranova; Pyraflam. (other products may be available) All fire-resisting glass should be marked, as a minimum, with an identifiable name or trademark, or other mark, capable of unambiguous identification to the manufacturer or supplier. For example, this could be a product name (as above), manufacturer s name or code. Safety Glass glazing that is marked BS6206:1981 or BS6262 is not fire-resisting glazing and the College Fire Safety Officer will require this to be replaced where appropriate. The College will also require documentary evidence detailing the performance of the glazing as it has been used in situ (and not a general certificate of performance for the product). Glazed apertures can potentially be the weakest part of any fire door if glazed incorrectly. For this reason, factory-glazed doors should be used wherever practicable, rather than glazing on site. Some integrity-only glasses, most notably modified toughened glasses, are sensitive with regard to edge cover and bead profile, and should always be installed in accordance with the manufacturer s instructions. Insulating glasses are more tolerant of glazing methods, but the bead fixings are critical and again the advice of the manufacturer should be sought and followed. Only complete tested glazing systems should be used. These should identify the glass product type and thickness, glazing seals, beads and fixings. Components within a glazing system should not be interchanged without relevant test evidence. 7

8 Due allowance should be made for expansion between glass edge and aperture. It is important, therefore, that apertures are cut accurately as recommended by the manufacturer. To meet the requirements of some independent certification schemes, the cutting of apertures for glass on site, is not permitted. Any cut-outs made to a door are likely to invalidate its certification. 2.7 Signage All Fire Doors MUST be provided with signs in accordance with BS ISO 7010:2011. These will be a minimum of 100mm x 100mm and preferably in rigid plastic, but maybe produced in other materials appropriate to the surface or the building design. Sign Description Positioned at eye level, on both sides of each fire door fitted with a selfclosing device. Positioned at eye level on the outer face of a fire door to a cupboard, store, plant room, riser etc, which does not have a self-closing device. Positioned at eye level on the visible face of a fire door which is fitted with a self-closer, but is held open by a device which releases the door on activation of the fire alarm. This is to prevent the door from being obstructed and unable to close. 3 KEY TO TERMINOLOGY AND ABBREVIATIONS Key Description Key Description FD30 A Fire Door with 30 minutes Integrity and Insulation properties (also shown as FD30/30) and complete with Intumescent Strips. FD60 Intumescent strips. (s) FRG30/60 VP Smoke Seals (use brush type, as these wear better than rubber blade type) often combined with the intumescent strips. Fire Resisting Glazing (30 or 60 minutes standard) Vision Panel required (if within a Fire Door, then must be FRG30/60 as above) SC FD30(s) SC & VP PB A Fire Door with 60 minutes Integrity and Insulation properties (also shown as FD60/60) and complete with Self-Closing Device complying with BS EN 1154: Door Closers Fire Door 30/30 with Intumescent Strips and Smoke Seals (usually combined), a Self- Closing Device and a Vision Panel. Push Bar/Panic Bar Emergency opening device complying with BS EN

9 General view of a Fire-resisting door and associated furniture (taken from the DCLG Guide to Fire Risk Assessment in Educational Premises) Alan Oakes Fire Safety Officer 01/05/2012 Version 1 9