Hydrostatic Test for Kitchen Suppression Systems

Hydrostatic Test for Kitchen Suppression Systems

Kitchen suppression systems are designed, tested, and approved to provide fire protection for commercial kitchen cooking appliances, hoods, and ducts. The suppression systems consist of an agent storage tank, manual release station, an automatic releasing mechanism, and supply piping that directs the agent to nozzles strategically positioned at heat sources in the kitchen. 

Kitchen’s hood suppression system includes a tank which contains the wet chemical suppression agent. Hydro testing is when that tank is removed from service and taken in for testing. 

The wet chemical storage tank, whether pre-pressurized or non-pressurized, will be emptied of the chemical suppression agent, then filled with water or oil. It will then be sealed and pressurized to two to three times its operating pressure, and it will be kept at that pressure for at least one minute. If the pressure holds, the tank has passed the hydro test. 

If the tank passes the test, it will be cleaned out and refilled with suppression agent to be put back in service. If it is a non-pressurized system that uses a cartridge, such as Ansul systems, then the cartridge must also be hydro tested or replaced at that time. 

Additionally, during this time, many companies like SSA Integrate will also replace your hood suppression system’s hoses as well. 

NFPA 17 requires that every 12 years the agent-holding tank, whether it is a pressurized or non-pressurized system tank, must be pulled out of service to be tested. But pre-pressurized systems have DOT requirements, requiring that the first test occur after 12 years, but then every 7 years after that, as they can weaken and lose their pressure over time. 

For all systems, the agent storage tank must be pressure tested to ensure the integrity of the cylinder. There are many types and manufactures of kitchen commercial wet chemical systems, each one has different test pressures for the cylinder, which are set by the manufacturer. Once filled with water, and sometimes oil, the cylinder is capped off, then pressurized to the manufacture test pressure and held at that pressure for no less than 1 minute. These systems are often tested to almost two times the service pressure.

On a non-pressurized system, there is a cartridge that pushes the agent out of the cylinder. This cartridge is replaced every 12 years. In some instances, these systems can have a burst disc that would need to be replaced before the 12-year hydrostatic test is scheduled.

Pressurized systems have valve stems, O-rings, and pins that need to be replaced. This is called a rebuild kit. Once all of the cylinders are tested, dried, and documented they get filled back up with the proper wet chemical agent and put back into service if there is not any issues with the test pressures. All systems, both pressurized and non-pressurized, get new agent during a 12-year hydrostatic test. For certain suppression systems, hoses will need to be replaced at the 12-year hydrostatic test.

Inspections, tests, and maintenance on kitchen ventilation hoods and fire suppression systems shall be performed in accordance with the manufacturer's instructions, NFPA 17 (latest edition), 17a (latest edition), 72 (latest edition), and NFPA 96 (latest edition). 

Monthly inspections are an important tool to ensure that your system stays in good working order. But inspections do not eliminate the need for routine maintenance of your system. NFPA 17A requires a full inspection of your system at least twice a year (semiannually) and after any activation.

Like your monthly inspections, these inspections must follow the manufacturer’s guidelines. However, they are much more comprehensive and detailed in nature and as such, require more time and expertise than monthly inspections do. At minimum, these inspections require the following:

❏ An evaluation of your system from a hazard perspective – Has the hazard changed in any way that might make the system less effective?

❏ An examination of every component of your system – This includes your fire detectors, the containers that hold the extinguishing agent, your system’s releasing devices, piping, hose assemblies, nozzles, and signals as well as any auxiliary equipment.

❏ A check of the agent distribution piping throughout your system – are there any obstructions that might prevent the release and/or proper flow of extinguishing agent?

❏ An examination of the wet chemical in your system – If there is any evidence of corrosion or pitting or structural damage to the cylinders, the chemical may not feed properly through your distribution system and should be replaced and the system recharged.

Monthly and annual maintenance tags shall be attached to each fire suppression system for recording the inspector’s initials, date, and confirmation on maintenance/inspections performed. Where fusible links are used, the manufacture and the installation dates for the links shall be marked on the system inspection tag. In addition, a signed and dated log of maintenance and a certificate showing date of exhaust system inspection or cleaning shall be available in the food service manager’s office and the facility manager’s office.

ITEM	ACTIVITY	FREQUENCY	NFPA REF
Extinguishing system nozzles are located directly above grease producing equipment	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
The Manual actuators are unobstructed	Inspection	Monthly	17A:7.2.2,
			17:11.2.1.1
The tamper indicator’s and seals are intact	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
The maintenance tag or certificate in place	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
No obvious physical damage or condition exists that might prevent operation	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
The pressure gauge(s) are in operable range.	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
The nozzle blow-off caps are intact and   undamaged.	Inspection	Monthly	17A:7.2.2
			17:11.2.1.1
Neither protected equipment nor hazard has been replaced, modified, or relocated	Inspection	Monthly	17:11.2.1.1
			17A: 7.2.2
Gas and electric power shutoff are operational	Test	Semiannually	17:11.3.1.4
Water-wash hood cleaning systems are operational in conjunction with hoods   protected by sprinkler systems	Test	Semiannually	96:11.2.1
Remove grease from exhaust system	Maintenance	Quarterly/ Semiannually	96 :11.3,
			96 :11.4,
Recirculating systems operation and safety interlocks perform in accordance with mfg’s instructions	Test	Every 6 mos or more frequently	96:13.6.5
Recirculating systems.  Electrostatic Precipitators cleaned	Maintenance	Weekly	96:13.6.3
Recirculating systems.  Clean entire hood Plenum and blower section.	Maintenance	Quarterly	96:13.6.4
Fixed temperature sensing elements of the fusible alloy type	Replace	Annually	17:11.3.2,
			17A:7.3.3,
			96:8.2.1.2
Clean fixed temperature sensing elements other than the fusible metal alloy type	Maintenance	Annually	17:11.3.3
			17A:7.3.4
Manual release stations are operational and send a signal to the building fire alarm control panel.	Test	Semiannually	17:11.3.1.4
			17A:7.3.2.3
Automatic release devices are operational and send a signal to the building fire alarm control panel.	Test	Semiannually	17:11.3.1.4
			17A:7.3.2.3
Water flow, valve tamper, and low water pressure cut-offs are operational	Test	Quarterly	72: Table
			7-2.2 - 13i
Examine detectors, expellant gas containers, agent containers, releasing devices, piping, hose assemblies, nozzles, signals, and all auxiliary equipment	Maintenance	Semiannually	17:11.3.1.
			17A:7.3.2.3
Verify that the agent distribution piping is not obstructed	Test	Semiannually	17:11.3.1
			17A:3.2.1
Examine dry chemical in stored pressure systems for caking	Inspection	Every 6 years	17:11.3.1
Hydrostatic pressure test on wet and dry chemical extinguishing systems (agent containers, aux. pressure containers, hose assemblies)	Test	Every 12 years	17:11.5.1
			17A:7.5.1

Ref:
NFPA 17 (latest edition), 17a (latest edition), 72 (latest edition), and NFPA 96 (latest edition).