Building Services Engineering Design 2 Module BNEE483

1. Hugo Gallagher Room M709 h.gallagher@gcal.ac.uk hugo@logis-tech.co.uk Tel: 0141 331 8836 Lecture 5 Building Services Engineering Design 2 Module BNEE483

2. Emergency Lighting Fire Precautions Act (HMG 1971) and Health and Safety Act (HMG 1974) make it obligatory to provide adequate means of escape in all places of work and public resort in the UK. Emergency lighting forms part of this requirement. BS 5266 (BSI 1975b) stipulates the min. standards for design, implementation and certification of such installations.

3. Emergency Lighting Consequences of the Great Fire of London in 1666 is that the UK has a long history of fire and safety legislation. Not so with other countries Some countries have no such legislation and some have different legislation to achieve similar standards. In the UK, there are variations in regulations at local levels due to different bye-laws in operation.

4. Emergency Lighting Legislation Emergency lighting is an essential part of the building services. Legal requirements which must be fulfilled at the time of commissioning of an installation. Principal statutory legislation is: Cinematograph Act 1952 Cinematograph Safety Regulations 1955 Factory Act 1961 Private Places of Entertainment Act 1967 Theatre Act 1968 Gaming Act 1968 Fire Precaution Act 1971 Health and Safety at Work Act 1974

5. Emergency Lighting Legislation Fire Certificates (Special Premises) 1976 Additionally there is much authoritative, non-statutory documentation which is quoted in specifications and licensing requirements by local fire authorities: Recommendations for Safety in Cinemas (HMSO) Hospitals Technical Memoranda nos.11 and 16 (HMSO) CIBSE Technical Memorandum TM12 Emergency Lighting (HMSO) IEE Wiring Regulations BS Code of Practice 1007

6. British Standard 5266 BS 5266 Emergency Lighting Parts 1 - 7 (BSEN 1838 (1999) is the equivalent of BS 5266 (Part 7) covers the requirements of emergency lighting. Not a legal document but into local bye-laws, then it can become one. Aim of the code is to promote wider understanding of different types of systems and give guidance on their correct application to the various requirements of different categories of premises. Often local authorities will modify the requirements, such as requesting higher illuminances. Enforcing authority (local authority) decides on the duration for which the emergency lighting must operate and this is usually from 1 to 3 hrs, a period greatly in excess of the evacuation time for a building.

7. Standardisation To standardise emergency lighting system design and equipment. To a degree, achieved nationally though variations in requirements occur locally. Internationally, standardisation is still being negotiated and there is, at present, no direct European equivalent of BS 5266 except for Part 7. Standardisation of emergency signs is in progress and where the British use worded signs, continentals desire symbols as used, for example, in standardised road signs. Seems a reasonable desire, but would have cost ramifications for British manufacturing in view of current stocks of what would ultimately become redundant emergency signs under a common European standard

8. Types of Emergency Lighting Emergency lighting can be split into two basic types: Standby lighting Escape lighting

9. Standby Lighting Some building areas cannot be evacuated immediately in the event of an emergency or failure of power supply because life would be put at risk Eg; a hospital operating theatre or a chemical plant process that requires a strict shut-down procedure. In such situations activities must proceed and standby lighting is required. This lighting is generally set by the situation requirements and attendant risks but, generally, level of lighting is set at 5 to 25% of normal installed lighting. Design follows normal interior lighting design requirements.

10. Escape Lighting Escape emergency lighting is provided to ensure the safe evacuation of a building: Indicate the escape routes clearly and unambiguously Illuminate the escape routes to allow safe movement to and out of the escape exits Ensure fire alarm points and fire fighting equipment along the escape route can be readily located All exits and emergency exits must have exit or emergency signs with an arrow and the word “EXIT” or “EMERGENCY EXIT” are required Signs must be illuminated at appropriate times so that they are clearly visible.

11. Operational Requirements BS 5266 defines min. standards of illuminance and operational requirements. Emergency lighting must reach its required level within 5 secs after failure of the main lighting system (or 15 secs, at the discretion of the local authority, for situations where occupants are familiar with the routes). Min. illuminance along centre line of escape route must be 0.2 lux or more. Ratio of the max. to min. illuminance along the centre line of the escape route must not exceed 40:1. This is to minimise contrast and allow eyes to rapidly adjust to the change in illumination on moving from max. to min. illuminances. These conditions apply to the whole area; halls and so on, where the whole area could form part of the escape route.

12. Glare Luminaires should not cause disability glare and are therefore mounted at least 2 m above floor level. Illuminated emergency signs must not be too high as they might become illegible in smoke.

13. Modes of Operation Systems and luminaires are normally categorised as follows: Maintained - Category M A lighting system where all emergency lighting lamps are in operation at all material times Non–maintained - Category NM A system where emergency lighting operates only when the normal supply fails Sustained - Category S A luminaire containing two at more lamps, at least one is fed from the emergency supply. Others energised from the normal supply. For compliance this type of system must be regarded as non-maintained.

14. Maintained Systems Usually found in places of entertainment and other premises where normal lighting may be reduced below that required for emergency purposes A suffix is added to the category ref. to indicate the hours duration in the event of a power failure. Ex, M/1 indicates a maintained system which will operate for one hr without mains power Category of system and duration of operation are usually

15. Luminare Positions Luminares should be positioned near each exit and at points where it is necessary to emphasise the position of potential hazards such as staircases and changes of direction or floor level Lifts should be illuminated even though they may not be used in the event of fire and each lift car requires emergency lighting. Escalators require the same level of illumination as the escape route (0.2 lux min.)

16. Main Locations where Emergency lighting Luminares are situated To show exit routes and final exits from buildings Signs should be illuminated Ensure that exterior areas of final exits are lit to at least the same level as the area immediately inside the building, to enable people to move away to a safe area

17. Near each intersection of corridors less than 2 m in width, as in fig 1

18. Near each change of direction for corridors less than 2 m in width as below

19. Near each staircase as in fig 3, so that each flight of stairs receives direct light (for corridors less than 2 m in width)

20. Near each staircase as in fig 3, so that each flight of stairs receives direct light (for corridors less than 2 m in width)

21. Near any change of floor level that may constitute a hazard (for corridors less than 2 m in width as shown below)

22. Main Locations where Emergency lighting Luminares are situated (cont’d) To illuminate fire alarm points and fire fighting equipment Ensure normal pedestrian escape routes from covered car parks are illuminated to the same standard as internal escape routes In plant, switch and control rooms Within passenger lifts cars In toilets exceeding 8 square meters

23. Planning a Scheme Design (1) Define the exits and emergency exits Mark the escape routes Identify problem areas; areas that will contain people unfamiliar with the building layout, toilets over 8 m2 area, plant rooms and escalators Mark on a plan the location of exit signs: self illuminated or by emergency lighting units nearby Determine where direction signs are required and necessary illumination

24. Planning a Scheme Design (2) Identify the area of the escape route which is already illuminated by the sign lighting Add luminaires to complete the illumination of the escape route; attention to stairs and other hazards {Allow for shadows, obstructions, bends in the route} Add extra luminaries to satisfy the requirements of the problem areas. Ensure sufficient exterior lighting is present for safe evacuation of the building Check all fire alarm call points and fire equipment stations have been dealt with.

25. Types of Escape Route Defined Escape Routes Undefined Escape Routes

26. Defined Escape Routes Specific route, normally a corridor or corridor area which must be kept clear at all times Horizontal illuminance at floor level on the centre line of a defined escape route should not be less than 0.2 lux Escape routes up to 2 m wide, 50% of the route width must be lit to a max. of 0.1 lux. {Lux figures are the min. level and in some instances (e.g. sheltered housing) levels must be higher} Data tables provided by suppliers of emergency luminaries to indicate means of achieving suitable lighting levels with particular fittings Colours and textures of décor also affect lighting levels. Interior designer needs informed of consequences; dark walls, ceilings For emergency lighting installations, the worst condition of zero reflectance should be assumed.

27. Undefined Escape Routes On an open plan layout. Often found in larger shops or offices Must be illuminated to an ave. of 1 lux with a uniformity of ±0.025. May appear to be a higher level of illumination, but in practise it is similar to the 0.2 lux max. in defined escape routes One advantage of using this undefined concept is that displays, furniture and other obstructions may be moved about without the need to change the emergency lighting system Calculations for numbers and positioning of emergency luminaries in undefined routes will follow standard lighting design calculations.

28. Fig 5 shows some typical photometric data for an emergency lighting luminaire,

29. Thorn EFV3 - Fig 6

30. EFV3 Data Sheet Data in fig 5 is based upon conditions at 25 °C Lumen output used is considerably lower than the normal lighting design figure of 420 lumen for the 300 mm 8 W tube, because the worst combination of conditions must be planned for If a designer fails to base a design on the correct “emergency lighting design lumens” figure, the scheme may not comply with the requirements and this may have legal consequences in the aftermath of an emergency.

31. Fig 7 – Spacing data for the EFV3 in a 2 m wide corridor

32. Fig 8(a) - Spacing data of fig 7 in use – Transverse spacing

33. Spacing data of fig 7 in use – axial spacing

34. Fig 8 (b)

35. Emergency Luminaire Glare Any scheme design should also consider the effects of glare An individual may be dazzled and escape hindered if there is a high contrast between luminaire and background Consideration is especially important in cases of congestion and panic. Glare zones are detailed for luminaries. Eg, max. intensity for Thorn luminaries is between 70° to 90°, as illustrated in fig 9 and represented in the spacing data in fig 7.

36. Fig 9

37. With a 3 m mounting height, max. intensity for transverse mounting its 12.2 candella and the cumulative limit for all visible luminaries along the escape route is 1860 cd, Equivalent in the axial direction is 1870 cd as recommended by the CIBSE. If no more than 3 luminaires are in view as in Fig 8(a), then the cumulative intensity is 36cd which is well within the recommended light Fig 7