1. Ventilation Using Shafts Colt Technical Seminar

2. I J OHea, Colt Founder I J OHea OBE (1897 - 1984) 2010 Group turnover 146 million Manufactures in the UK, Holland, Germany, Saudi Arabia, China and Singapore A private company founded in 1931 A brief history of Colt 3. Current UK Business markets Solar Shading Natural Ventilation Louvre Environmental Comfort Control Smoke Control 4. Ventilation using shafts 5. Ventilation Using Shafts 1. Ventilation of Fire Fighting Stairs: Natural Ventilation to BS 5588 Part 5 Natural Shafts to BS 5588 Part 5 BRE Shafts to BS 5588 Part 5 Mechanical Shafts 2. Ventilation of Common Corridors in Residential Developments: Natural Ventilation to ADB 2006 Natural Shafts to ADB 2006 Pressurisation/Mechanical Ventilation to ADB 2006 3. Extended Travel Distances in Common Corridors Using Mechanical Shafts Covering: 6. General Description: A common shaft passing through multiple levels allowing natural or mechanical ventilation to the fire floor via the use of dampers or automatic opening devices on each level. Used for: Ventilating fire fighting lobbies to assist fire fighting operations from a fire fighting shaft and/or Ventilating common corridors in high rise residential developments. Ventilation Using Shafts 7. 1. Ventilation of Fire Fighting Stairs A fire fighting shaft will mostly, but not exclusively, be required to serve: 1. The upper storeys of any building where a floor level is more than 18m above fire service vehicle access level. 2. The basement storeys of any building with a basement storey more than 10m below fire service access level. A fire fighting shaft will require a protected staircase, a fire fighting lift and a fire fighting lobby and should have smoke control to comply with BS 5588 Part 5: 2004. Ventilation Using Shafts 8. The upper storeys in Shop, Commercial, Assembly, Recreational and Industrial buildings with a storey of 900m2 or more which is more than 7.5m above fire service vehicle access level. 1. Ventilation of Fire Fighting Stairs Ventilation Using Shafts 9. Fire Fighting: In fire fighting shafts the fire and rescue services need clear access to every level. Usual fire fighting protocol is to take the lift to a floor below the fire floor, connect to the dry riser and then ascend to the fire floor by stair. The primary objectives of the ventilation system are, therefore: to prevent smoke spread into the staircase to improve conditions in the fire fighting lobby. 1. Ventilation of Fire Fighting Stairs Ventilation Using Shafts 10. Stairwell ventilation A 1.5m2 openable vent at the head of the stairwell; or A 1m2 openable window at each storey (OV) Lobby ventilation A 1m2 vent (OV) in the fire fighting lobby; or A 3m2 shaft with 1.5m2 dampers on each level with openings at the top and bottom of the shaft; or The BRE Method, which is as above, but omits the opening at the bottom of the shaft. BS 5588 Part 5 provides prescriptive ventilation recommendations 1. Ventilation of Fire Fighting Stairs Ventilation Using Shafts 11. A 3m2 shaft is connected to the lobbies by 1.5m2 dampers at high level. Only the damper on the fire floor opens Air inlet is provided via the stairs from the final exit door and a 1m2 ventilator at the head of the stairs No air inlet is required at the base of the shaft replacement air is drawn from the staircase, preventing smoke flow into the stair. 1. Ventilation of Fire Fighting Stairs BRE Shaft Ventilation Using Shafts 12. Visibility in onerous wind conditions 1. Ventilation of Fire Fighting Stairs BRE Shaft Ventilation Using Shafts 13. The next obvious step Offers a further reduction in the occupied space taken up by the system If effective could be used for both fire fighting and means of escape 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 14. The major challenge is to avoid excessive depressurisation of the lobby to prevent smoke being drawn in and problems opening doors negative This can be avoided by: Low level inlet An inlet shaft Doors to be open Grilles in doors Variable speed fans Fire Fighting Lobby Staircase 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 15. We have developed a standard system that will be at least as good as the BRE smoke shaft and better in adverse wind conditions The system comprises: a small vertical shaft 0.6m2 instead of 3.0m2 a variable speed extract fan set (run and standby) a pressure sensor in each lobby a small motorised damper to each lobby a 1m2 stairwell ventilator 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 16. Mechanical ventilation 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 17. The design has been proven by CFD analysis By replicating the BRE shaft CFD analysis after discussion with BRE By optimising the air flow rate and shaft and damper dimensions to match the BRE shaft By modelling closed door conditions to ensure that the system: Does not draw excess smoke into the lobby with doors closed (smoke seal doors between lobby and accommodation are needed for this) 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 18. Visibility - doors open Mechanical shaft BRE shaft 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 19. Ventilation Using Shafts 20. Installations: Newhall Street, Birmingham 6 Levels Unite, Bond Street, Bristol 2 systems at 10 levels each Thames Tower, Leicester 2 systems at 16 levels each Threadneedle St, London 6 Levels Moseley St, Manchester 9 Levels Univ of Sheffield LRC 7 Levels Shoreditch Hotel, London 6 Levels Twickenham RFU 4 Systems of 6+ levels each Vincent Hotel, Southport 7 Levels Hatton Gardens Liverpool 2 Systems at 9 levels each London School of Economics 4 shafts at 11 levels each typ. 21 Great Winchester Street 6 Levels C & A Bournemouth 1 shaft Quartermile, Edinburgh 5 No Mechanical Shafts 1. Ventilation of Fire Fighting Stairs Colt Shaft Ventilation Using Shafts 21. 2. Ventilation of Common Corridors in Residential Developments In multi-storey residential buildings, the main escape route is always via common corridors and/or lobbies to protected stairs. Smoke spread to the corridor from a fire in an apartment is unavoidable as the occupants make their escape. The 2006 version of ADB requires common corridors which contain a staircase to be ventilated. Fire fighting stairs in residential buildings do not require a separate ventilated fire fighting lobby. The ventilation system allows the smoke in the corridor to be cleared and ensures that smoke is prevented from entering the staircase, which could make make escape difficult for occupants of higher storeys should the whole building need to be evacuated. Ventilation Using Shafts 22. Small Single Stair Apartment Buildings Top floor level no more than 11m above ground level No more than 3 storeys above ground level Stair does not connect to covered car park ADB Requires: Openable vent (OV) to each landing level of stair or single OV at head of stair with activation from bottom of stair. Also: If lobby is ventilated, travel distance from apartment to stair can be increased from 4.5 to 7.5m. Ventilation Using Shafts 23. All Other Apartment Buildings ADB Requires: All corridors/lobbies adjoining stairs to be ventilated by either natural or mechanical means. The staircase requires a vent with a free area of 1.0m2 from the top storey to outside. Activation: If a single stair building, the vents should be automatic via smoke detectors in the common access space. If a multi-stair building, the ventilation can be manual, BUT the vent at the top of the stair must be interlinked to open at the same time. Ventilation Using Shafts 24. Common Corridors can be ventilated, either: Naturally, located on an outside wall with a minimum free area of 1.5m2. Naturally, discharged into a vertical smoke shaft, closed at the base. Mechanically, using extract and natural inlet or supply fans. Mechanically, using pressure differentials, in accordance with BS EN 12101- 6: 2005. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments 25. SHAFT Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Ventilation 26. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Minimum Free Area under the 2000 edition of ADB 27. Definition of Minimum Free Area, either: The aerodynamic free area of the ventilator as defined in EN 12101 Part 2: 2003 Specification for natural smoke and heat exhaust ventilators. Or: "the total unobstructed cross sectional area, measured in the plane where the area is at a minimum and at right angles to the direction of air flow" Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments 28. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Minimum Free Area under the 2006 edition of ADB 29. If a shaft system is used, the following criteria should be met: The Shaft should: Be closed at the base Have a minimum cross-sectional area of 1.5m2 with a minimum dimension of 0.85m in either direction. Extend at least 0.5m above the highest structure within 2m Extend 2.5m above the ceiling of the highest level served by the shaft. The vent into the shaft, the vent at the top of the shaft and any safety grilles in the shaft should all have a minimum free area of 1.0m2. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Shafts 30. Construction: The shaft should be constructed from non-combustible material and the vents should be equivalent to a E30Sa fire door. The shaft should be vertical with no more than 4m at an inclined angle (max 30) Operation: On detection of smoke in the corridor, the vent on the fire floor, at the top of the shaft and the top of the stair should all open simultaneously vents on all other levels should remain closed. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Shafts 31. Exhaust opening Ventilation damper Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Shafts 32. Typical Roof Installation: Natural Ventilation Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments 33. Internal Damper to shaft, concealed by decorative grille: Equivalent to E30S Fire rated construction Motor open/closed Natural, minimum free area 1.0m2 Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Shafts 34. Colt Doorman Actuator with fire door to shaft: Equivalent to E30S Fire rated construction Require a safety grille across shaft at each level Units on other levels must lock closed to prevent smoke transfer Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Natural Shafts 35. Approved Document B permits the use of mechanical ventilation for smoke control of common escape routes but gives no design guidance on how to design such a system. However based on the experience gained in developing the Colt Shaft for fire fighting applications, several options are available to reduce the natural shaft from 1.5m2 to 0.6m2 using a mechanical system. As with the fire fighting system, the main objective is to keep smoke from entering the staircase. Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Mechanical Shafts 36. Internal Damper to shaft, concealed by decorative grille: Equivalent to E30S Fire rated construction Motor open/closed Mechanical - Typically 0.8m2 Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Mechanical Shafts 37. Supply air Distribution Ductwork Pressure Relief Air Release Ventilation Using Shafts 2. Ventilation of Common Corridors in Residential Developments Pressurisation 38. An extended lobby can be used to reduce travel, but the lobby ..must not provide direct access to any storage room, flat or other place containing a potential fire hazard. 3. Means of Escape Systems Extended Travel 7.5m7.5m+ Ventilation Using Shafts 39. ADB 2006 states: There may be some instances where some increase on these maximum figures [travel distances] will be reasonable. In most circumstances mechanical systems can be designed to enhance safety. 3. Means of Escape Systems Extended Travel Ventilation Using Shafts 7.5m7.5m+ 40. 3. Means of Escape Systems Extended Travel Options: i. Natural Exhaust/Mechanical Inlet ii. Mechanical Extract/Natural Inlet iii. Mechanical Extract/Mechanical Inlet Ventilation Using Shafts 41. 3. Means of Escape Systems Extended Travel Natural Exhaust/Mechanical Inlet Has been used by various fire engineers with varying degrees of success. Positively pressurises the corridor, therefore can risk pushing smoke into other apartments and staircase. Ventilation Using Shafts 42. 3. Means of Escape Systems Extended Travel Natural Exhaust/Mechanical Inlet 7.5m7.5m+ Ventilation Using Shafts 43. 3. Means of Escape Systems Extended Travel Mechanical Extract/Natural Inlet Slightly depressurises the corridor, therefore inlet shaft and dampers need to be sized carefully to avoid creating a pressure greater than 50 Pa. Typically, inlet shaft will need to be in order of 1.5m2. Ventilation Using Shafts 44. 3. Means of Escape Systems Extended Travel Mechanical Extract/Natural Inlet 7.5m7.5m+ Ventilation Using Shafts 45. On a recent project the Travel Distance was successfully extended from 7.5m to 18m in one direction System modelled in both escape and fire-fighting mode and compared with a compliant corridor with a natural AOV system. System out-performs natural AOV for both evacuation and for fire- fighting 3. Means of Escape Systems Extended Travel Mechanical Extract/Natural Inlet Ventilation Using Shafts 46. Modelled to compare with compliant 7.5m corridor with AOV in still wind conditions with growing fire in apartment. Smoke spills into corridor during evacuation and then again 10 minutes later when fire brigade arrive, fire has grown to around 5000 kW Compliant Corridor Extended Corridor 3. Means of Escape Systems Extended Travel Ventilation Using Shafts 47. Compliant AOV Extended Mechanical System 7.5m AOV Apartment Door 18m Mechanical Extract Inlet Apartment door Dense Smoke Clear Air 3. Means of Escape Systems Extended Travel Ventilation Using Shafts 48. 3. Means of Escape Systems Extended Travel Mechanical Extract/Mechanical Inlet Reduces size of inlet shaft to 0.6m2 typically. Extract to be designed as Colt Shaft without pressure sensing, inlet fan to match extract rate. Ventilation Using Shafts 49. 3. Means of Escape Systems Extended Travel Mechanical Extract/Mechanical Inlet 7.5m7.5m+ Ventilation Using Shafts 50. 3. Means of Escape Systems Extended Travel Mechanical Extract/Mechanical Inlet Reversible Particularly useful with a central stair to two extended corridors. Fans need to be truly reversible (standard fans run at approx 60% in reverse), or additional inlet may be necessary. Detection needs to identify smoke location. Ventilation Using Shafts 51. 3. Means of Escape Systems Extended Travel Mechanical Extract/Mechanical Inlet Reversible A further benefit of this system is that fire fighters can override the system so that both fan systems can be set to extract, allowing an enhanced clearance system. 7.5m7.5m+ 7.5m 7.5m+ Ventilation Using Shafts 52. 3. Means of Escape Systems Extended Travel Mechanical Extract/Mechanical Inlet Reversible Ventilation Using Shafts StairSupply Exhaust 7.5m + 7.5m + Smoke can be controlled depending on the fire location 53. Installations: Means of Escape Systems: Junction Apartments, Didsbury Trout Road, West Drayton 67 Barking Road, London Leicester Square, Leicester Oxford Street, Leicester Pinner Road, Harrow The Conneries, Loughborough Canal Street, Nottingham Great Guildford Street, London Great Western Quarter Red Lion Square, London Hepburn House, Westminster 3. Means of Escape Systems Mechanical Systems Ventilation Using Shafts Extended Corridor Systems: Angel Meadows, Manchester Plymouth Grove, Manchester John Bright Street, Birmingham Greenwich Millennium Village, London Pan Peninsula, London Quartermile, Edinburgh Brabazon House, London Parkwood Mills, Huddersfield 54. The work of the BRE has resulted in alternative methods of ventilation being considered, which have now been incorporated into the new Approved Document B. This has paved the way for many new developments in the use of mechanical ventilation shafts in numerous applications. The performance of natural ventilation and AOVs can sometimes be questioned and the use of mechanical ventilation with a known extract rate can be shown to be beneficial for both fire fighters and building occupants. Conclusions Ventilation Using Shafts 55. The End Any Questions?