Understanding the Hazards Multidimensional Human Factor, catering staff, building management. (concerned with providing good food) Food preparation area, range tops, (concerned with food hygiene) Ventilation Equipment Maintenance (called in when something doesnt work) These people are working with heat and may not be aware of the risks, for example of not maintaining equipment.
What can be seen in a restaurant ….What cannot be seen
Development of Wet Chemical Innovation in commercial food preparation techniques e.g. Vegetable cooking oils. Energy efficient appliances. Leading to; Increased fire losses, failure of BC dry chemical. In Nov 1994 UL launched UL300 Fire Testing of Fire Extinguishing Systems for Protection of Restaurant Cooking Areas UL300 considers Cooking Appliance Design Cooking agent ignition characteristics Worst case scenarios Plenum Hood and Duct (existing standard )
Classification of Fire BS 7937:2000 Classifies a class F fire as fire in cooking appliance that involves combustible cooking media. (vegetable or animal oils and fats) (Class K in American system) Suitability of extinguishing agent ABC Dry Powder has never been suitable UL fire testing demonstrates BC dry powder is ineffective. EN3Pt 7 2007 considers it hazardous for powder and CO2 fire extinguishers to be used on class F fires.
Incompatibility of Agents What is wrong here? Cooking Range Class F Fire fighting equipment Class ABC & B
Suitability of Fire Fighting Equipment Fire Blankets Fire test described in BS:EN 1869:1997 allows a 2 min pre burn. However, the gas supply is isolated when the fuel ignites at approx 350 to 370 (AIT) Blanket is positioned and left in place for 17 mins. Many reports of fire blankets not working possibly because the fire point would be in excess of 370 c or intervention has not been immediate Germany has banned the use of fire blankets in commercial cooking operations. Reported 70,000 fires in a 5 year period. (Both commercial and domestic)
Origin and Development of Standards (Commercial cooking operations) First considered by NFPA in 1946 (this was mainly as a result of fire losses in the newly emerging fast food industry) This first standard became NFPA 96 (which has undergone many revisions over the years the latest being 2013) Wet chemical extinguishing systems first considered by NFPA in 1983 this became NFPA17A( NFPA17 Dry Chemical) When specifying it is the norm to quote NFPA96/17A
Standards NFPA 96:Standard for Ventilation Control and fire Protection of Commercial Cooking Operations 2013 Ed. NFPA 17A:Standard for Wet Chemical Extinguishing Systems 2009 Ed. HVCA:Standard for Kitchen Ventilation Systems DW171 LPS 1223: VdS (Germany) France Portugal Ireland Requirements and testing procedures for LPCB Certification and listing of fixed fire extinguishing systems for catering equipment Testing of kitchen protection equipment. INTEO500763A Artigo 194 No national standard (use international standards) pr EN 16282 PT7 2011 Equipment for commercial kitchens Installation and use of fixed fire suppression pr EN 50613 ASHRAE Tests on devices for fire prevention and suppression on hobs.
Guidance LPC/FPARecommendations for fish and chip frying ranges (16A) LPC/FPARecommendations for cooking equipment (16B) NHS EstatesHTM 2025 Pts. 1 to 4 Ventilation in Healthcare premises Building Services Research & information Ass. (BSR1A) LB65/94 Ventilation of Kitchens Association of British Insurers BSRIA Fire Risk Assessment Catering Extract Ventilation HSEMaintenance, examination and testing of local exhaust ventilation HVCATR/17, DW144, TR/19 BS 5588 PT9Code of practice for ventilation and air conditioning ductwork International building Code
Fire Protection of Commercial Cooking Operations Fire Test Video
Fire Protection of Commercial Cooking Operations Ansul Range Guard Pyrochem Amerex Buckeye Nobel Wet Chemical Fire Suppression Distributors
Fire Protection of Commercial Cooking Operations Exhaust System (canopy, filters, ductwork) Cooking Equipment Maintenance Fire Extinguishing System Fire Fighting Equipment Responsibility (rests with owner) Training Components
Fire Protection of Commercial Cooking Operations Access Panels
Fire Protection of Commercial Cooking Operations Exhaust System NB Fire Dampers not permitted on exhaust system. Yes on supply air.
Fire Protection of Commercial Cooking Operations Types of Canopies (hoods)
Fire Protection of Commercial Cooking Operations Types of Canopies (hoods) Ventilated Ceiling Typical Water Wash Plenums
Fire Protection of Commercial Cooking Operations Shall be designed and installed in accordance with NFPA 96/17A Shall be both automatic and manual Shall comply with UL300 Shall be provided with fuel shut off Shall be provided with system annunciation Shall be installed by a certified installer. Fire Extinguishing System
Myths Associated with Wet Chemical Systems System is stand alone Does not need any interface FalseWet chemical systems are a component of an integrated system (NFPA 96) Very basic fire safety principals are upon discovering a fire raise the alarm where possible isolate power supply prior to fighting the fire Wet chemical systems require annunciation and power isolation
Fire Extinguishing Systems Two Types Single shot Continuous discharge Single shot System comprises of a pre-determined number of agent tank or tanks sufficient to suppress and control a fire in the protected area. Appliance specific nozzle location
Fire Extinguishing Systems Two Types Overlapping Protection Allows for relocation of cooking equipment Non appliance specific
Fire Extinguishing Systems Two Types Continuous Discharge
Fire Extinguishing Systems Two Types Extinguishing Agent Extinguishers shall use agents that saponify, class B shall not be used. Wet chemical (Trade name Ansulex) An aqueous solution of organic or inorganic salts or a combination thereof that forms an extinguishing agent (NFPA17A) Extinguishing Mechanism: When applied results in a rapid spreading of vapour suppressing foam on the fuel surface. The foam extinguishes and secures the flame by forming a barrier between the liquid fuel and oxygen. The cooling effect lowers the temperature (by at least 10 degrees C) and decreases fuel vapour release (NFPA17A) (Saponification?)
Fire Protection of Commercial Operations How it works
Fire Extinguishing Systems Nozzle Placement (Extract)
Kitchen Fire Protection Wet chemical suitability/ assessment Project KitchenYesNoRemarks Enclosed Opene.g. Theatre style kitchen Ductwork Fire Rated Protectede.g. Via fire rated enclosure No Protection Interfaces Fire Alarm Power source/Gas, Electrical BMS Wet chemical system type One Shot Continuous Discharge Additional Protectione.g. Water mist enclosure
In this project the feature is for a full view of the cooking operation. Commercial cooking operations: Are areas of special fire risk [TGDB] Desirable that kitchen be separated from their associated restaurant by fire resisting construction. (BS5588-6:1991) Building Regulations
Where it is impracticable to comply fully with TGDB – Alternative solutions may be considered Compensating fire safety measures may also be necessary e.g. Enhanced levels of life safety protection Building Regulations
Traditionally fire resisting roller shutters have been used to complete the enclosure of the kitchen in the event of a fire. It was considered this solution was not viable and so innovation has been introduced.
AQ2000 Low Pressure Water Misting System Demonstration
Conclusion: Hazards: The main hazard is the ventilation canopy and extract system (the core safety hazard) Cooking equipment is primarily an ignition source
Other Factors: Poor cleaning of extract system Poor duct design i.e. 90 change in direction, use of screws to secure ductwork rather than welding or liquid seal rivets. Structural construction and conditions for the exhaust ductwork i.e. horizontal ductwork Poor installation
Other Factors: Largely dependent on kitchen working procedures e.g. oil changes in fryers Cooking methods (woks can lead to large flames) Higher cooking temperatures leads to more grease being transferred into vapour. Dependant on temperature of grease and grease residues.
Fire Containment Theory Assumptions: Exhaust system of liquid-tight solidly welded construction, is not heavily contaminated with grease. Exhaust system extracts and drains the maximum amount of grease in order to limit amount of fuel in the ductwork. Exhaust system is regularly cleared. Fire containment is the responsibility of the exhaust system not the fire suppression system (which should be considered an extinguishing system) Grease fire can reach temps of 1260 C Cooking area is enclosed in fire resisting construction
Other Factors A la carte use of standards (mismatch) No electrical interfaces (fire alarm, power isolation) Incorrect fire fighting equipment No training No fire safety management Cooking operation is not code compliant e.g.
Conclusions contd Fires in commercial cooking operations (CCO) is a complex subject Greater fire safety is achieved at the design stage where all parties are consulted and the information is communicated to the builders owners and users. Fire in CCO can be devastating so we should be more pro-active in prevention