Fire Prevention - Commercial Kitchens, Extract Systems and Cooking Ranges

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Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 1: Introduction

Commercial Kitchen Ranges Commercial kitchen ranges and their integral extract ducting are located within many buildings such as restaurants, hotels, airports, fast food outlets, works canteens and shopping centres.

Cooking activities present a variety of fire risks which need to be identified, fully assessed and appropriately controlled, to prevent damage to property and any associated interruption to the business

It is therefore essential that kitchen ranges and extract ducting systems are suitably designed, installed and maintained, with inspection and cleaning undertaken at appropriate intervals and the provision of suitable fire detection and fire protection measures.

It is generally accepted that a significant percentage of all commercial fires are kitchen-related, with most occurring within the canopy above the cooking range and the associated extract ducting, primarily due to the build-up of combustible cooking oil deposits and fats that accumulate over a period of time.

A poor extract duct cleaning regime will be a significant contributory factor to kitchen fires and may aid fire spread throughout the property.

Fires also occur in the kitchen itself, either on or within the cooking range below the extraction system, or within adjacent cooking equipment. Provided these fires do not spread to the extract ducting they are generally easier to contain and extinguish This is especially true if there are: ✔ Automatic or manually actuated fixed fire suppression systems in place ✔ Appropriate interlocks to de-energise or isolate the firing or power to the cooking equipment ✔ Trained personnel who are able to use fire blankets and/or manual fire extinguisher appliances of the appropriate type, which are designed for fires involving hot cooking oils and fats

Which of these provides an environment for fires to start and then spread quickly or widely.

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 2: Risk Assessment

Additional Guidelines The best practice guidance set out in the Building Engineering Services Association (BESA) TR 19® Grease Specification for Fire Risk Management of Grease Accumulation within Kitchen Extraction System Guidelines, should help inform this assessment.

It should also be used to identify the necessary steps to be taken in the future, including maintenance, to help ensure that kitchen extraction systems remain safe at all times.

Further guidance can also be found in the UK from the RISCAuthority in their publication - RC68: Recommendations For Fire Safety in Catering Establishments.

Alongside all that was mentioned, it is crucial that organisations have robust management systems in place for employee training, housekeeping and maintenance as part of a joined-up risk management strategy

Causes of Kitchen-Related Fires Known causes of fires within commercial kitchens are as follows: ✔ Spontaneous combustion of fat deposits that have built-up within the extract filter, canopy, plenum and/or ductwork ✔ Short circuit or overheating of an electrical appliance (e.g. a fan) in the extraction ductwork, causing a spark or heat to ignite any grease/fat build-up within the extract filter, canopy, plenum and/or ductwork ✔ A spark, flame, ember or hot gas that travels from the cooking range into the extract filter, canopy, plenum and/or ductwork and ignites any fat build-up Attention should also be given to pizza ovens, tandoor ovens, etc. ✔ Extract ducting which can be extensive and circuitous in design, before exiting the building making it difficult to clean throughout Poor design that results in increased accumulation of combustible fat, oil and grease deposits in extract ducting ✔ Overheating and/or spilling of oils, grease and fats either on the cooking range or deep fat fryer ✔ Overfilling of fryers when changing or replenishing oil ✔ Spillage of cooking oils/fats in the kitchen area ✔ Operation of deep fat fryers with insufficient depth of oil to adequately cover the heating elements ✔ Cooking equipment thermostat failure and failure of an over-temperature cut-out device ✔ Heat sources such as electrical plates, ovens, grilles, bratt pans, griddles, broilers, rotisseries, frying equipment, etc., or ancillary processes involving flames or production of hot gases ✔ Cooking equipment left unattended during operation ✔ Ignition of ordinary combustible items within the kitchen such as towels, aprons, paper, cardboard, packaging, etc. ✔ Operator error such as an individual doing something incorrectly ✔ Hot work on extract ducting or close to the extraction network

Which of these are known causes of fires within commercial kitchens

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 3: Fire Protection and Methods to Reduce the Incidence of Kitchen Fires

Fire Protection and Methods to Reduce the Incidence of Kitchen Fires One of the most important factors in reducing kitchen fires is to prevent the build-up of combustible fat-contaminants within the non-combustible extract ductwork.

There are a number of methods that can aid this objective, the most important being an effective deep clean of the whole extraction system by an accredited cleaning contractor.

This provides far greater assurance that the cleaning and maintenance of ductwork systems has been carried out correctly

The contractor should be third party certificated under one of the following accreditation schemes: BESCA - Building Engineering Services Competence Assessment Ltd - Ventilation Hygiene Elite Scheme Loss Prevention Certification Board scheme LPS 2084 Requirements for the approval and listing of companies carrying out inspection, cleaning and maintenance of ductwork systems

Further benefits of using accredited contractors include: Supporting compliance with fire safety legislation Work will be undertaken in accordance with BESA TR19 Grease guidelines which will help reduce fire risks Avoids wasting resources searching for and engaging with inappropriate service providers Ensuring that appropriately trained and competent individuals undertake cleaning work Identification and recording of areas of limited or restricted access where inspection, cleaning and maintenance are impractical and reporting these limitations to the client Documentation and correct reporting for the work undertaken to satisfy TR19 Grease guidelines Provide recommendations for access improvements to better facilitate the ongoing cleaning and maintenance of the ductwork system. They may also make recommendations on the need for additional grease traps or adjustments to the frequency of cleaning. Accredited companies are audited to ensure that they continue to meet high standards of workmanship and adhere to the requirements of TR19 Grease and the accreditation scheme

To establish the rate of build-up, which of these will you have to take into consideration?

There are a number of other practices which will help eliminate or reduce the severity of fires. Let's learn about them on the next lesson.

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 3: Fire Protection and Methods to Reduce the Incidence of Kitchen Fires Part II

Regular cleaning of all equipment, including deep cleaning of the entire extract ductwork, based on a risk assessment

Regular servicing and maintenance of all cooking equipment/appliances and electrical installations as part of a preventative maintenance programme

Cooking oils and fats should be changed regularly

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 4: Fire Compartmentation, Fire-Resistant Ducting and Ducting Exit Point

Additionally, there should be a full understanding of the duct exit point, the location of the extract ducting and what this potentially exposes, e.g. combustible roof deck; combustible wall construction; yard storage; roof mounted equipment, etc.

Recognised fire-resistant ducting should be installed within all fire compartments to limit fire and smoke spread throughout the building. Where the ducting passes through any fire compartment walls this vulnerability should be assessed and appropriate protection provided.

The number of bends/changes in direction of the extract ducting should be kept to a minimum and should ideally be zero. Changes in direction cause the entrained fat droplets within the air to be deposited on the ductwork wall

The point where the ducting exits a building should be fully assessed. This should include an assessment of the wall or roof construction and in particular any combustible construction or combustible exposure.

A fire in the ducting will exit at this point and could possibly ignite the construction or a combustible exposure. This exit point should be regularly reviewed to monitor fat/grease deposits and cleaned.

Where the ducting passes through any combustible construction, the construction needs to be protected from excessive heat and the ducting encased in materials affording at least 1 hour fire-resistance.

Reference should be made to further guidance on fire resistance requirements within the following : BESA - DW172: Specification for Kitchen Ventilation Systems Besa - DW144: Specification for Sheet Metal Ductwork

Which of these should be included in the Fire Compartmentation Strategy of the Site?

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 5: Deep Cleaning and Frequency

Deep Cleaning and Frequency Aside from the build-up of a combustible lining in a non-combustible duct, the build-up of fat deposits in an extract duct can affect the efficiency of the extraction system. As a result, it is essential that all parts of the extraction ducting are readily accessible to enable cleaning, including any motors and fans.

An inspection of the system by an accredited specialist cleaning company engineer should confirm that suitable access is available to the entire ductwork system.

Deep cleaning frequency of the entire extract duct, fan and motors should be based on a risk assessment.

Specialist accredited contractors should provide relevant and adequate information and in accordance with BESA TR19 Grease requirements

A TR19 Grease compliant report will include : Completion certificate(s) Pre and post-clean readings of grease levels throughout the extraction ductwork system Pre-agreement with the customer of a specific section or area that is not to be cleaned A clear statement (Yes or No) indicating whether or not the system was cleaned in its entirety. If the answer is No, the report must state precisely what was not cleaned and why A recommendation for cleaning frequencies based on the pre-clean grease thickness test readings The frequency of cleaning is based on keeping grease levels below 200 microns (the maximum level), across the entire extraction ductwork. An assessment table is included in the report. Readings of grease levels (in microns) for the stated test locations and the mean (average) micron reading across all micron readings should also be included. A sufficient number of photographs of the system taken before and after cleaning that are representative of the system condition A schematic diagram or, as-installed drawing of the system layout showing the system in its entirety including known components, changes of direction, access panels, areas that could not be cleaned Recommendations made where access has been problematic for remedial actions, e.g. access panels to be added Other hazards that have been identified Observations and further recommendations

Which of these are included in a TR19 Grease compliant report? (Select all that apply)

Commercial Kitchens: Extract Systems and Cooking Ranges Lesson 6: Removing Fat Deposit Build-up

UV (Ultraviolet) Filtration

As a result: The cleaning costs may be reduced, as there are less deposits and therefore it takes less time to deep clean the duct, or In some cases (subject to approval) the frequency of the deep cleaning may be modified to a lower frequency The odour emissions at the extract outlet are reduced, which is an added environmental benefit of the UV filtration.

Wood-Fired Ovens, Barbecues and Biomass Water Heaters Where wood-fired bakery ovens, barbecues fired with charcoal or wood, and water heaters fired with biomass are provided as part of a commercial kitchen fit-out, a smoke, grease and soot filtering and spark arrestor system should be provided.

The system should be an extract hood cold water mist/water wash based system located directly at the point of extract from the source within the extract hood. It should be fitted with automatic water flow control to minimise water consumption when not required.

A carbon monoxide (CO) sensing system should be installed in the kitchen/restaurant space local to the charcoal/wood/biomass-fired equipment. This sensing system should enable the ventilation system in the space, to ensure that no build-up of CO gases occurs during unoccupied and occupied periods

Carbon monoxide is a colourless, odourless, and tasteless flammable gas that is slightly less dense than air. It is a poisonous gas to humans, which in some cases of prolonged exposure can lead to unconsciousness and death.

As a result, these ovens should only be operated where carbon monoxide detection is provided. It is strongly recommended that wood-fired operations and barbecues must not be undertaken internally within buildings.

Commercial Kitchens: Extract Systems and Cooking Ranges Additional Sources & Useful Links

Inspection/Auditing Tools iAuditor Provides digital tools that work on mobile/tablet devices that enables your teams to carry out area inspections and can allow completion of a permit to work. Contact Milly Wallace​ on aviva@safetyculture.com or call 0161 768 1124. Further information is available HERE .

You can also checkout the Commercial Kitchens - Extract Systems and Cooking Ranges Checklist - Aviva Loss Prevention Standard - Property V1.1 on iAuditor's Public Library.