4 August Islington Fire Protection Transpower NZ Limited

Transcription

1 4 August 2011 Islington Fire Protection

2 Contents 1. Introduction...1 General Approach General Notes Description of Building Areas...4 Use, Layout, Fire Load, Criticality and Division...4 Construction and Dimensions...5 Exposure, Separation and Fire Systems Required Performance Levels Fire Scenarios Risk Improvement Options Cost of Options...16 Recommendations Scope of Work Conclusions...21 Appendix A: Costing Spreadsheets Marsh i

3 1 Introduction Marsh was recently involved in a High Impact Low Probability (HILP) event study for the Islington substation. One for the key conclusions of the analysis was that the most significant HILP exposure for the site is from a fire in or around the control building. An indicative high level cost benefit analysis indicated that a business case exists for upgrading and extending the fire protection provided in the control building. The scope of this study is to build upon the earlier HILP study and specifically to: 1. Develop fire protection concept design options for the control building, this would be expected to include (but not be limited to) consideration of: Sprinkler protection (standard and pre-action) Extended aspirating smoke detection coverage Deluge systems (dry pipe open head systems) Gas flood systems (room and cabinet designs) Extending conventional detection system coverage Upgrade of fire and smoke separations within the control building and between the control building and neighbouring areas. Fire rating of cables and equipment cabinets. Fire load and ignition source control measures. 2. Although focussed on the control block the study will also consider protection of and against a fire in the adjoining condenser crane hall building. Costs and options for this aspect will be separately detailed. 3. Develop detailed budget estimates for these design alternatives 4. Select preferred approach from alternatives based upon costs and benefits. 5. Develop performance specification for preferred option at a level of detail suitable for competitive tender of the required work. Marsh 1

4 General Approach The general approach is as follows: 1. Document current arrangements 2. Document required performance levels 3. Identify fire scenarios 4. Identify concept designs for these scenarios which will meet the required performance levels. Marsh 2

5 2 General Notes Relay room and communications room are critical areas with lots of unused or non critical use spaces around them. Fire separation between areas is generally incomplete with concrete walls but no formal fire doors or doors which have been sealed by dry-wall construction. Doors generally on closures but latching of these not always correct. Doors are solid core but not tagged as fire rated doors. Service/cable penetrations would also require sealing in some locations. Some potential for exposure through windows to the control building. Including building to building from the condenser hall and also from external fire loads notably transformers and diesel oil storage. Glazing is generally Georgian wired but there are a number of opening windows. Some potential for link bridges to act as a conduit for fire spread. Fire load is highest in the condenser hall which is partially separated from the control building. External exposure from service transformers and oil storage for emergency diesel. Marsh 3

6 3 Description of Building Areas Table below summarises building areas. The first table summarises the use, layout, fire load, criticality and division of these spaces, the second table covers the construction, and dimensions, and the third table considers exposure, separation and existing systems. Use, Layout, Fire Load, Criticality and Division Location Use Fire Load Criticality Degree of Division Downstairs Main Entry Lobby and toilets Low Low High. Enclosed under stairs Lunchroom and corridor Staff lunch area Moderate Low Moderate. Relay Room Communications Room Relay equipment. 7 banks 600mm wide by 10m long Comms equipment. 6 banks of panels. Moderate High None Moderate High Low (sub floor space) Control Room Some storage, equipment Moderate Low Low (suspended ceiling) Control Room Corridor Some storage, equipment Moderate Low Low (suspended ceiling) Office Corridor Some storage, equipment Moderate Low Low (suspended ceiling) Offices Storage, equipment, furniture High Low High (suspended ceiling) Training Room Storage, equipment, furniture High Low Low (suspended ceiling) Training Room Kitchen Storage, equipment, furniture Moderate Low Low Training Area Lobby Entrance lobby Low Low Low Cable Basement Cable routing High High Low Bridge Access way Low Low Low Condenser Hall Workshop/Condenser Hall High Moderate Low Marsh 4

7 Construction and Dimensions Location Construction Dimensions [m] Length Width Height Downstairs Main Entry Concrete Lunchroom and corridor Concrete Relay Room Mainly concrete (600mm deep beams 2.65m spacing) Georgian wired glazing. Communication Room Mainly concrete (600mm deep beams 2.65m spacing) (4.3) Georgian wired glazing. Control Room Concrete, drywall, Georgian wired glazing Control Room Corridor Concrete, drywall Office Corridor Concrete, drywall Offices Concrete, drywall, standard glazing Training Room Concrete, drywall, standard glazing Training Room Kitchen Concrete, drywall, standard glazing /0 Training Area Lobby Concrete, drywall, standard glazing Cable basement Concrete, drywall, Georgian wired glazing Bridge Concrete, Georgian wired glazing Condenser Hall Concrete, Georgian wired glazing Exposure, Separation and Fire Systems Location Exposure to Separation Fire Systems Downstairs Main Entry Cable Gallery Concrete, NR door, low fire load Heat Condenser Hall Concrete, NR door, low fire load Lunchroom Open Stair, low fire load Lunchroom and corridor Relay Room Concrete, NR door, low fire load in corridor Heat Condenser Hall Concrete, NR door, some potential via glazed areas, low fire load in corridor Relay Room Lunchroom Concrete, NR door VESDA Control Room Drywall construction, suspended ceiling Comms Room Concrete, NR door Training Room Kitchen Concrete, NR door Training Room Concrete wall Communications Room Relay Room Concrete, NR door VESDA Training Room Kitchen Drywall construction, openings at low level Condenser Hall Concrete, NR door, low fire load Control Room Relay Room Concrete, drywall. Partial VESDA, Control Room Corridor Drywall Heat Control Room Corridor Relay Room Drywall Partial VESDA, Control Room Drywall Heat Office Corridor Concrete, NR door Training Room Concrete, NR door Marsh 5

8 Office Corridor Control Room Corridor Concrete, NR door Heat Training Room Drywall, NR door Offices Drywall, NR doors, glass Offices Office Corridor Drywall, NR doors, glass Heat Training Room Office Corridor Drywall, NR door Heat Control Room Corridor Concrete, NR door Relay Room Concrete, NR door Training Room Kitchen Drywall, NR door Training Room Kitchen Training Room Drywall, NR door Heat Relay Room Concrete, NR door Comms Room Drywall construction, openings at low level Training Area Lobby Cable Basement Concrete, drywall Heat Office Corridor Open stairwell Cable Basement Training Area Lobby Concrete and drywall construction Smoke Downstairs Main Entry Concrete and NR door Bridge Relay Room Concrete and NR door Heat Condenser Hall Concrete and NR door Condenser Hall Bridge Concrete and NR door Smoke Downstairs Main Entry Concrete and NR door CO 2 Gas Flood Marsh 6

9 4 Required Performance Levels The requirements for the fire protection system concept design are assumed to be as follows: Provide fire protection commensurate with the fire risk exposure for the various areas of the control block. This would be expected to result in the focus being on protection for the cable basement, relay/equipment room and communications room. Comply with the requirements of the New Zealand Building Code (and any other applicable regulatory requirements). To give some indication of typical levels of performance for high criticality electrical equipment rooms Marsh 7

10 FM Data Sheets NFPA 850 IEEE Std 979 External FM m Separation (<5000l) Large Transformers ( 2000l) Transformers 2 hour fire resistant 15m Separation ( 5000l) 15.2m Separation OR Exposing Buildings 1 construction OR 2 hour fire wall 6.1m + 2 hour fire wall 1.5m Separation (<1900l) Small Transformers (<2000l) 4.6m Separation (1900l - <75kVA 3m Separation 19000l) kVA 6.1m Separation 7.6m Separation (> 19000l) 333kVA 9.1m Separation Non-combustible construction 4.6m Separation (<1900l) 7.6m Separation (1900l l) 15.2m Separation (> 19000l) Combustible construction 7.6m Separation (<1900l) 15.2m Separation (1900l l) 30.5m Separation (> 19000l) External FM m Separation (<5000l) Large Transformers ( 2000l) Transformers 1.5m Separation (<1900l) 15m Separation ( 5000l) 9.1m Separation OR Exposing Another 7.6m Separation (1900l - OR 2 hour fire wall 1 hour fire wall Transformer l) 15.2m Separation (> 19000l) OR 2 hour wall Fire separations DS 5-3 requires use of non 2 hour between control room Performance based combustible construction for and switchrooms requirement to provide switchrooms no specific fire separation in line with largest separation requirements. credible fire exposure. Switchroom Provide brigade connected Smoke detection to be Desirable to install smoke/heat Protection photo or photo-ion smoke installed. detection. detectors. Consideration to be given to Consideration to be given to If grouped cable present 3 sprinklers if there is significant sprinklers if there is significant provide either sprinkler cable loading. cable loading. protection or gas flood (in addition to smoke detection). Control Room Provide brigade connected Smoke detection. Desirable to install smoke/heat Protection photo or photo-ion smoke Consideration to be given to detection. detectors. High sensitivity pre-action sprinklers. Consideration to be given to detection to be considered. Consideration to be given to sprinklers if there is significant Consideration to be given to gas flood systems for cable loading. 1 Distances measured from edge of oil containment to building line. If fire wall used this must extend such that the line of sight separation distances to the exposed building are within the limits given. 2 Distances measured from edge of oil containment to closest surface of exposed transformer. 3 Unless FM Global Group 1 cable. Marsh 8

11 gas flood systems for underfloor cable and/or room if underfloor cable and/or room if critical equipment present critical equipment present. Sprinklers recommended. Cable tunnels Fire sprinklers/deluge. Early warning fire detection. Sprinklers or gas flood to be considered. Consideration of sprinkler protection. Fire protective coating or covering. Exterior Hydrants. Hydrants recommended. NA Marsh 9

12 5 Fire Scenarios The following fire scenarios have been identified based upon start location. # Start Location Immediate Effects Spread Potential 1 Cable Basement Damage to cable trays, smoke spread up into relay and/or comms rooms Fire spread via cable penetrations to relay room. Fire spread through unrated wall section to lobby and offices at East End of Building. If not controlled potential to spread through upper floor and then through unrated wall into comms room. Fire spread through main entrance lobby doorway and up stairs into lunchroom area. Limited credible spread potential for fire given lack of fire load and separations. 2 Relay Room Damage to equipment in cabinet, spread of smoke. Significant involvement of cable or other combustibles allows significant damage through the area. Some potential for fire spread outside of the relay room if there is build-up of combustible storage, furnishings, etc., in the room and/or the doors are not secured. 3 Comms Room Damage to equipment in cabinet, spread of smoke. Significant involvement of cable or other combustibles allows significant damage through the area. Some potential for fire spread outside of the comms room if there is build-up of combustible storage, furnishings, etc., in the room and/or the doors are not secured. 4 External Transformer Damage to transformer and neighbouring area. Spread to comms room though open Georgian wired window. Likely exposure is only smoke only given height of glazing however potential for fire spread cannot be ruled out. Also running pool fire affecting cable running in trenches in front of the transformers (understood to be cabling relating for the condensers and not regarded as being critical compared to other cabling. Need to confirm that this could not spread from here to impact cable basement). Marsh 10

13 5 Training Kitchen 4 Damage to kitchen area some smoke spread to comms room. 6 Main Smoke spread to relay room. lobby/lunch room 7 Condenser Hall Smoke spread to comms room (via bridge) and relay room via lobby. Fire spread via unrated wall to comms room with substantial damage to comms room. Spread into training room area and then through remainder of floor. Potential for spread to relay room. Given low fire load limited potential for fire to break through to relay room providing that doors are maintained closed. Potential for large fire. Fire transfer via bridge or lobby cannot be ruled out but is considered unlikely. Also potential for fire spread via windows. The following potential additional controls are identified for each scenario # Start Location 1 Cable Basement 2 Relay Room Additional Controls Sprinkler Protection Check and upgrade cable penetration seals Replace doors with fire doors (and upgrade dry wall) Provide Intumescant coating on cables. Gas flood Sprinkler Protection Comment High effectiveness. Deals with all fire types and limits both damage and spread potential Should be undertaken as a maintenance activity Limited benefit if sprinklers installed. Limits involvement of cables. Not regarded as reliable as sprinkler protection. May affect the rating of cables. Given volume of space and nature of fire load then gas flood is not considered a practical alternative to sprinklers. It could be used in the battery rooms if these were considered to be critical. High effectiveness. Deals with all fire types and limits both damage and spread potential 3 Comms Room Check and upgrade any cable penetration seals Replace doors with fire doors (and upgrade dry wall) Gas flood Sprinkler Protection Should be undertaken as a maintenance activity Limited benefit if sprinklers installed. Gas flood provides earlier suppression than sprinklers and can penetrate into concealed spaces. Options to be considered included room gas flood as well as in cabinet gas flood. High effectiveness. Deals with all fire types and limits both damage and spread potential Check and upgrade any cable penetration seals Replace doors with fire doors (and upgrade dry wall) Should be undertaken as a maintenance activity Limited benefit if sprinklers installed. 4 Selected as the most credible scenario for a fire starting in this part of the building. Marsh 11

14 4 External Transformer 5 Training Kitchen 6 Main lobby/lunch room 7 Condenser Hall Gas flood Deluge/Sprinkler over transformer Relocation of units away from building Providing bunding to limit extent of oil spread Provide sprinkler protection over glazing into comms room above the transformer. Sprinkler protection through area Replace doors with fire doors (and upgrade dry wall) Provide drenchers over unrated doors and construction Check and upgrade any penetration seals Gas flood Alter use of area Sprinkler protection through area Alter use of area Replace doors with fire doors Provide drenchers over unrated doors and construction Sprinkler protection through area Replace doors with fire doors Provide drenchers over unrated doors and construction Provide drenchers over exposed glazing Gas flood provides earlier suppression than sprinklers and can penetrate into concealed spaces (including sub floor spaces). Options to be considered included room gas flood as well as in cabinet gas flood. Limits damage to neighbouring unit but of marginal value. Practical difficulties in doing this. May have limited benefit if exposures from a running oil fire are modest. However it should be relatively cheap. Low incremental cost if sprinkler protection installed into comms room. Sprinkler protection throughout space would be effective but would be at considerable cost given non critical nature of area. Would reduce risk of fire spread (as alternative to sprinklers) Provides potentially lower cost alternative to upgrading fire doors and drywall construction. Should be undertaken as a maintenance activity for separations connecting critical areas. Gas flood provides earlier suppression than sprinklers and can penetrate into concealed spaces (including sub floor spaces). Options to be considered included room gas flood as well as in cabinet gas flood. Changing area so it is no longer a kitchen or ideally changing whole area (kitchen, training room, offices, etc) so that it is not in use. Sprinkler protection throughout space would be effective but area is non critical nature of area so decision may be based on cost benefit. Changing lunch room area so it is no longer a cooking area would reduce risk. Could lunch area be located outside of the control building? Limited benefit if sprinklers installed. Provides potentially lower cost alternative to upgrading fire doors and drywall construction. Sprinkler protection throughout space would be effective but would be at considerable cost given size and relatively non critical nature of area. Limited benefit if sprinklers installed. Provides potentially lower cost alternative to upgrading fire doors and drywall construction. Low incremental cost if sprinkler protection already installed into exposed rooms. Marsh 12

15 General Measures (covering multiple locations) Review prevention activities including housekeeping, ignition control, thermography, etc. Hydrant/hydrant riser provision Conformal coating of circuit boards Power down of equipment on confirmed fire signal Design/alteration of cabinets so that they will not admit smoke. Smoke seals on doors Low cost items which should be incorporated into any programme to improve the fire risk of the control building. Improves chance of effective intervention by the fire brigade. Reduces damage to circuit boards. Reduces damage to equipment. Reduces damage to equipment. Reduces potential for smoke spread. Low cost item so may be worth doing even though incremental effect may be small if in an area where sprinklers are installed. Marsh 13

16 6 Risk Improvement Options Based on the previous analysis the potential 5 protection scheme (scope of work) is as follows: Item Cable Basement Relay Room Comms Room Lobby/Lunchroom Condenser Hall Training Area Kitchen Training Room Disused Offices Control Room Area External Transformer Sprinkler Protection Gas Flood Upgrade Fire Doors Install Smoke Seals Drenchers over Doors/Unrated Walls Drenchers over Glazing Check Penetrations Relocate/Change Use Bunding Intumescent Coating of Cables Hydrant/Riser Coverage Conformal coating of circuit boards Power down of equipment Cabinet Design Prevention Activity Review 5 Where the colour coding is interpreted as follows; green expected to be undertaken unless cost benefit is unfavourable, yellow possibly undertaken based on cost benefit, red not expected to be done unless cost benefit indicates otherwise, blank (white) not considered to be applicable. Marsh 14

17 The cost of the options is discussed in the next section. Marsh 15

18 7 Cost of Options The cost of the options is summarised below, costing spreadsheets for each option are presented in Appendix A. Protection Option Cost [$,000] (Note 1) Cable Basement Sprinkler Protection (Note 2) 137 Critical Areas (Note 2, 3) Sprinkler Protection 186 Relay Room Gas Flood (Note 4, 5) 150 Communications Room Gas Flood (Note 4, 5) 115 Control Building Sprinkler Protection (Note 2) 262 Control Building and Condenser Building Sprinkler Protection (Note 2) 365 Notes: 1. All values include a 15% contingency 2. Assumes 50m trench connection and some connection cost allowance. Costs would reduce by approximately $20k is connection could be made direct off supply into building. Assume no pump boost is required, if required allow nominal $20k. Assumes no tank required, if tank and pump required allow nominal $50k. 3. Critical areas are relay room and communications room. 4. Assumes current VESDA systems suitable for interfacing to gas flood system. 5. Assumes no major building works associated with making room gas tight. 6. Assumes pre-action systems not required for electrical equipment rooms. Costing of other risk improvement options is estimated below (costs are estimates only) Risk Improvement Option Cost [$] Upgrade Fire Doors 1,200 per door Install Smoke Seals 300 per door Drenchers over Doors/Unrated Walls 300 per door Drenchers over Glazing 300 per window Marsh 16

19 Check Penetrations Relocate/Change Use Bunding Intumescent Coating of Cables Hydrant/Riser Coverage Conformal coating of circuit boards Power down of equipment Cabinet Design Prevention Activity Review 5,000 (nominal) 10,000 (nominal) 2,000 (nominal) 10,000 (nominal) Full Ring 100,000 (nominal) Partial coverage 5,000 Undefined Undefined Undefined Undefined Based upon the above costs and the indicated risk improvement options in Section 6 the following options are identified and costed. Item Sprinkler Protection Gas Flood Additional Costs Total Cost Option 1: No additional protection systems Option 2: Sprinkler Protection to cable basement. Upgrade local fire doors Option 3: Gas Flood to critical areas. Upgrade local fire doors Option 4: Sprinkler Protection to cable basement. Upgrade local fire doors. Gas Flood to critical areas. Option 5: Sprinkler Protection to cable basement and critical areas. Upgrade local fire doors. Option 6: Sprinkler Protection to cable basement and critical areas. Upgrade local fire doors. Gas Flood to critical areas. Option 7: Sprinkler Protection throughout control building Option 8: Sprinkler Protection throughout control building. Gas Flood to critical areas Option 9: Sprinkler Protection throughout control and condenser building Option 10: Sprinkler Protection throughout control and condenser building. Gas Flood to critical areas Pros and cons of the options are discussed below: Option Pros Cons 1 Lowest cost Limited protection. 2 Low cost No protection to electrical rooms 3 High level of protection to electrical equipment rooms No protection to cable area. No protection from fire starting outside of electrical rooms. 4 High level of protection to electrical equipment rooms. No backup in event of gas protection system failure. Marsh 17

20 Protection of basement. 5 High level of protection to electrical equipment rooms. Protection of basement. 6 Highest level of protection to electrical equipment rooms. Protection of basement. 7 High level of protection to electrical equipment rooms and rest of building. Protection of basement. Easy to demonstrate compliance with Building Code. 8 Highest level of protection to electrical equipment rooms and rest of building. Protection of basement. Easy to demonstrate compliance with Building Code. 9 High level of protection to electrical equipment rooms, rest of building and condenser hall. Protection of basement. Easy to demonstrate compliance with Building Code. 10 High level of protection to electrical equipment rooms and rest of building and condenser hall. Protection of basement. Easy to demonstrate compliance with Building Code. No protection from fire starting outside of electrical rooms. Potential for significant damage to electrical equipment rooms prior to sprinkler system activation. Limited protection from fire starting outside of electrical rooms. Potential for significant damage to electrical equipment rooms prior to sprinkler system activation. High cost. High cost. High cost. Recommendations Option 6 ($468k) provides a high level of protection (to critical areas) at a moderate cost. Installation can be designed to allow future extension of coverage. Option 4 ($419) provides a high level of protection (to electrical equipment areas) at a moderate cost. It is suggested that option 2 ($152k) only be considered as an initial stage prior to undertaking additional works. Option 8 ($542k) would be required if strict compliance with the sprinkler standard is a critical factor for Transpower. It also provides the highest level of protection against a fire starting in the non critical areas of the building (training area). However from a risk basis it is arguably difficult to justify the additional cost associated with this option. Additional costs of options 7, 9 10 are not considered to be warranted for the benefits achieved. The next section details the scope of work for the recommended options. Marsh 18

21 8 Scope of Work Option Scope of Works All options Sprinkler Water Supply (town main supply class C supply) Connection to main via trenched underground pipework Sprinkler system valveset (including enclosure for this) Brigade inlet connection OH3 sprinkler system (to NZS 4541) throughout cable basement Hydrants (on isolation valves) fed off underground pipework from towns main (number and location to be defined as part of detailed design). Fire brigade (control room) signalling equipment and panel. Interfacing to building evacuation system. Smoke sealing of internal doors and checking door closure reliability of doors from cable basement, relay room and communications room. Checking the fire separation from the cable basement, relay rooms and communications and repairing and/or improving this as necessary. Review potential for relocating transformers and diesel storage away from control building. Additional for Option 2 Providing drencher sprinklers over outside faces of internal doors leading into cable basement. Additional for Option 4 Additional for Option 6 As per option 2, plus the following Gas flood system (Inergen, FM200 or equivalent) covering relay room and communications room Interfacing of gas flood system to VESDA system (or replacement/upgrade of VESDA system if necessary). As per option 4, plus the following Sprinkler protection of relay and communication room (including subfloor space). Sprinkler protection of lunchroom, corridor and lobby areas including into bridge linkway. Sprinkler protection over unrated wall sections and doors between sprinklered and unsprinklered areas including but not limited to: Sprinklers over external face of doors leading from entrance lobby into condenser hall Sprinklers over external face of unrated walls separating relay and communication rooms from unsprinklered areas. Sprinkler protection over windows in communication room exposed by transformers and Marsh 19

22 diesel storage (if not relocated as discussed above). Providing drencher sprinklers over outside faces of internal doors leading into cable basement. Marsh 20

23 9 Conclusions The analysis has identified fire protection options for the Islington Control Building. Based on this the option which appears to provide a high level of risk protection for a moderate cost is option 4 (sprinkler protection of the cable basement and gas flood of critical electrical equipment rooms). Given the relatively small marginal cost increase to extend sprinklers into these areas there is also a strong case for option 6 (as option 4 plus sprinkler protection of electrical equipment rooms and exposing areas). There is a degree of uncertainty over the performance of the local fire fighting water supplies (though discussions with FPIS indicated supplies in the area are relatively strong) and until test results are available it cannot be stated with confidence that the supplies will not require boosting. In addition need clarity around exact location that Transpower can connect into the towns main. This issue could be left open in the performance specification (for the contractor to determine once they have been awarded the contract) or could be determined in advance and supplied as part of the tender package. Contractors could also be asked to cost separate options (e.g. options 4 and 6) or a decision could be made in advance as to the option which is preferred and the tender based upon this. In addition to the active fire protection works there is also a number of work items (e.g. checking and upgrading fire penetrations, fitting smoke seals to doors, etc) that would be typically undertaken by a passive protection company. This could be managed through the active fire protection contractor as a sub contract or Transpower could engage direct. Marsh 21

24 Marsh 22

25 Appendix A Costing Spreadsheets Marsh 23

26 Figure A1 Sprinkler Protection Cable Basement Only Figure A2 Sprinkler Protection Cable Basement, Relay Room and Communication Room Only Marsh 1

27 Figure A3 Sprinkler Protection throughout Control Building (not Condenser Building) Marsh 2

28 Figure A4 Sprinkler Protection throughout Control Building and Condenser Building Marsh 3

29 Marsh 4

30 Marsh Ltd Level 18, 151 Queen Street PO Box 2221, Shortland Street Auckland 1140, New Zealand