11.5 Inspection, Testing, and Maintenance of Listed Hoods Containing Mechanical, Water Spray, or Ultraviolet Devices Listed hoods containing mechanical or fire-actuated dampers, internal washing components, or other mechanically operated devices shall be inspected and tested by properly trained, qualified, and certified persons every 6 months or at frequencies recommended by the manufacturer in accordance with their listings.
11.6 Cleaning of Exhaust Systems
11.6.1* Upon inspection, if the exhaust system is found to be contaminated with deposits from grease-laden vapors, the contaminated portions of the exhaust system shall be cleaned by a properly trained, qualified and certified person(s) acceptable to the authority having jurisdiction.
11.6.2* Hoods, grease removal devices, fans, ducts, and other appurtenances shall be cleaned to remove combustible contaminants prior to surfaces becoming heavily contaminated with grease or oily sludge.
11.6.3 At the start of the cleaning process, electrical switches that could be activated accidentally shall be locked out.
11.6.4 Components of the fire suppression system shall not be rendered inoperable during the cleaning process.
11.6.5 Fire-extinguishing systems shall be permitted to be rendered inoperable during the cleaning process where serviced by properly trained and qualified persons.
11.6.6 Flammable solvents or other flammable cleaning aids shall not be used.
11.6.7 Cleaning chemicals shall not be applied on fusible links or other detection devices of the automatic extinguishing system.
11.6.8 After the exhaust system is cleaned, it shall not be coated with powder or other substance.
11.6.9 When cleaning procedures are completed, all access panels (doors) and cover plates shall be restored to their normal operational condition.
11.6.10 When an access panel is removed, a service company label or tag preprinted with the name of the company and giving the date of inspection or cleaning shall be affixed near the affected access panels.
11.6.11 Dampers and diffusers shall be positioned for proper airflow.
11.6.12 When cleaning procedures are completed, all electrical switches and system components shall be returned to an operable state.
11.6.13 When an exhaust cleaning service is used, a certificate showing the name of the servicing company, the name of the person performing the work, and the date of inspection or cleaning shall be maintained on the premises.
11.6.14 After cleaning or inspection is completed, the exhaust cleaning company and the person performing the work at the location shall provide the owner of the system with a written report that also specifies areas that were inaccessible or not cleaned.
11.6.15 Where required, certificates or inspection and cleaning and reports of areas not cleaned shall be submitted to the authority having jurisdiction.
11.7 Cooking Equipment Maintenance
11.7.1 Inspection and servicing of the cooking equipment shall be made at least annually by properly trained and qualified persons.
11.7.2 Cooking equipment that collects grease below the surface, behind the equipment, or in cooking equipment flue gas exhaust, such as griddles or char broilers, shall be inspected and, if found with grease accumulation, cleaned by a properly trained, qualified, and certified person acceptable to the authority having jurisdiction.
A.11.6.2 Hoods, grease removal devices, fans, ducts, and other appurtenances should be cleaned to remove combustible contaminants to a minimum of 50 µm (0.002 in.).
When to clean: A measurement system of deposition should be established to trigger a need to clean.
The method of measurement is a depth gauge comb, shown in Figure A.11.6.2, which is scraped along the duct surface. For example, a measured depth of 2000 µm (0.078 in.) indicates the need to remove the deposition risk. The system would also include point measurement in critical areas. For example, 3175 µm (0.125 in.) in fan housing requires cleaning.
* Reproduced with permission from NFPA® 96: Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, Copyright© 2014, National Fire Protection Association. This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.