Brian Bourke - Engineers Ireland [PDF]

Presentation to Engineers Ireland

“Hazards Associated with Commercial Cooking Operations” B. Bourke BSc MSc F.I.Fire E. Fire Eng. Tech. MCIOB, Registered Building Surveyor.

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+ hotel

Vilnius Shopping Mall (2009)

Year 2011

Year 2015

Year 2015

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

doesn’t work) These people are working with heat and may not be aware of the hazards, for example of not maintaining equipment.

What can be seen in a restaurant

….What cannot be seen

Origin and development of standards video

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:

“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)

VdS (Germany) France Portugal Ireland pr EN 16282 PT7 2011

“Equipment for commercial kitchens” “Installation and use of fixed fire suppression”

pr EN 50613

“Tests on devices for fire prevention and suppression on hobs .

ASHRAE

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)

Myths Associated with Wet Chemical Systems System is stand alone Does not need any interface False

Wet 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

Guidance LPC/FPA

Recommendations for fish and chip frying ranges (16A)

LPC/FPA

Recommendations for cooking equipment (16B)

NHS Estates

HTM 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”

HSE

“Maintenance, examination and testing of local exhaust ventilation”

HVCA

TR/17, DW144, TR/19

BS 5588 PT9

“Code of practice for ventilation and air conditioning ductwork”. International building Code/ Fire code

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 cleaned.  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

Fire Protection of Commercial Cooking Operations Types of Canopies (hoods)

Example 1

Fire Protection of Commercial Cooking Operations Types of Canopies (hoods) Ventilated Ceiling

Typical Water Wash Plenums

Fire Protection of Commercial Cooking Operations Components  Exhaust System (canopy, filters,  

   

ductwork) Cooking Equipment Maintenance Fire Extinguishing System Fire Fighting Equipment Responsibility (rests with owner) Training

Fire Protection of Commercial Cooking Operations Exhaust System

NB Fire Dampers not permitted on exhaust system. Yes on supply air.

Example 8

What you do not see

Example 6

Example 5

Fire Protection of Commercial Cooking Operations Access Panels

Fire Protection of Commercial Cooking Operations Fire Extinguishing System  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 Systems Extinguishing Agent 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?)

Extinguishers shall use agents that saponify, class B shall not be used.

Other Factors Cooking operation is not code compliant e.g.

 A la carte use of standards (mismatch)  No electrical interfaces (fire alarm, power isolation)  Incorrect fire fighting

equipment  No training  No fire safety management

Fire Extinguishing Systems Two Types Single shot

Single shot Continuous discharge

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

Suitability of Fire Fighting Equipment Cooking Range Class F

What is wrong here?

Fire fighting equipment Class ABC &B

Incompatibility of Agents

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”.

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)

Fire Protection of Commercial Operations

How it works

Fire Extinguishing Systems Nozzle Placement (Appliance)

Fire Extinguishing Systems Nozzle Placement (Extract)

Fire Extinguishing Systems Detection

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.

Conclusions cont’d  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

Thank You

Questions

Fire Protection of Commercial Cooking Operations Wet Chemical Fire Suppression Distributors

 Ansul  Range Guard  Pyrochem

 Amerex  Buckeye  Nobel

Building Regulations In this project the feature is for a full view of the cooking operation. Commercial cooking operations: Are areas of special fire risk [TGD”B”] “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 TGD”B” – “Alternative solutions may be considered” “Compensating fire safety measures may also be necessary” e.g. Enhanced levels of life safety protection

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.

Fire Extinguishing Systems Maintenance  Semi Annual  Annual  10 Year Maintenance

VIDEO

Example 2

Example 3

Example 4

Example 7