UL 300 Fire Testing of Fire Extinguishing Systems for Protection of Commercial Cooking Equipment
Cooking Areas Protected With Multiple Nozzles
Drip Pans For Indicated Appliances
Fabricated Appliances / Commercially Available Unit
Appliances with Faster Cooling Rates than 5 °F per Minute
Clarify Current Test Procedures
These requirements cover the performance during fire tests of pre-engineered fire extinguishing system units intended for the protection of commercial cooking equipment for restaurants, cafeterias and other similar venues. For installation requirements, see the following documents: NFPA 17, UL 300 Standard for Dry Chemical Extinguishing Systems; NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations; and NFPA 17A, Standard for Wet Chemical Extinguishing Systems. Note that local authorities having jurisdiction should be consulted prior to installation.
UL 300 pre-engineered fire extinguishing system units, agents, or both are required to comply also with the requirements for construction and performance as applicable to specific types, designs, sizes, and arrangements; and all such additional requirements which apply are not within the scope of these requirements for fire tests.
The term “product” as used in this standard refers to all fire extinguishing systems or any part thereof covered by the requirements unless specifically noted otherwise.
Components
Except as indicated in 2.2, a component of a product covered by this standard shall comply with the requirements for that component.
A component is not required to comply with a specific requirement that:
- a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard, or
- b) Is superseded by a requirement in this standard.
A component shall be used in accordance with its rating established for the intended conditions of use.
Specific components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specified limits, and shall be used only under those specific conditions.
Units of Measurements
UL 300 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information.
Undated References
Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard.
COOKING APPLIANCE
A cooking device that has or is capable of having a surface of liquid grease or one in which grease is involved, such as a deep fat fryer, griddle, range, chain broiler, electric char-broiler, charcoal broiler, mesquite broiler, gas-radiant char-broiler, wok, tilt skillets, and similar appliances. The protected area is limited to the cooking surfaces of the appliance only.
CYLINDER/VALVE ASSEMBLY
A container that incorporates a valve and that provides storage of the extinguishing agent and expellant gas until the valve is actuated. For cartridge operated units, this assembly includes the extinguishing agent storage container and cartridge mechanism. When actuated, the valve releases the agent into the distribution network of the extinguishing system.
DISCHARGE RATE
The ratio of the quantity of agent discharged from a nozzle to the discharge time measured within ±1 second. When a minimum discharge rate is indicated, reference is made to the minimum quantity of agent discharged and the time measured within ±1 second.
DISCHARGE NOZZLE
A device that is used to uniformly distribute the extinguishing agent over or into a specific area.
DISCHARGE TIME
The time interval between the first appearance of extinguishing agent at the nozzle and the time at which the discharge becomes predominantly gaseous.
DUCT (OR DUCT SYSTEM)
A continuous enclosed passageway for the transmission of air and cooking vapors.
EXPELLANT GAS
Dry nitrogen, dry air, or other gas used to facilitate the discharge of the extinguishing agent.
EXTINGUISHING SYSTEM UNIT
Identified components that are assembled into a system for the discharge of an extinguishing agent through fixed piping and nozzles for the purpose of extinguishing fires.
GAS CARTRIDGE
A container that provides storage for an expellant gas.
GREASE
For test purposes, grease is new vegetable shortening incorporating an anti-foaming agent. For hood and duct and broiler testing only, grease shall be new or used vegetable shortening, or rendered animal fat.
GREASE FILTER
A component of a grease vapor removal system that deflects the air and vapors passing through it in such a manner as to result in the grease vapors to concentrate, condense, or both, for the purpose of grease collection.
HOOD
A device provided as part of an exhaust system to direct and capture grease vapors and exhaust gases from a cooking appliance.
LOW QUALITY FATTY BEEF STEAKS
Steaks that contain 20 – 30 percent fat or gristle, well marbled, and uniform in size. An example of a cut of meat which meets the requirement is “goose neck round,” which is 70 – 80 percent lean.
UL 300 MANUAL MEANS OF ACTUATION
A means of system actuation in which the system operator initiates system discharge.
OPERABLE PRESSURE RANGE
The pressure range corresponding to the pressures in the storage container at the specified minimum and maximum temperatures for which the extinguishing system unit is intended to be operable.
OPERATING PRESSURE
The pressure in a fully charged container at 70°F (21°C).
PLENUM
The volume of enclosed space between the grease filters and the portion of the hood above the grease filters in a hood and duct system.
PRE-ENGINEERED SYSTEM
A system that is tested in accordance with the limitations prescribed by the manufacturer for maximum and minimum pipe lengths, accessories, number of fittings, number and types of nozzles and nozzle placement, types of fire risks and their maximum areas, volumes, or both areas and volumes of protection.
UL 300 PRESSURE VESSEL (CYLINDER)
A container that provides storage for the extinguishing agent and expellant gas, or when used at a location remote to the extinguishing system unit, provides storage for expellant gas.
TILT SKILLETS/BRAISING PANS
Cooking devices which are intended to braise, simmer, saute, or fry foods.
Cooking Appliance Extinguishment Tests
UL 300 An extinguishing system unit is to be tested with each type of cooking appliance with which it is intended to be used. Specific cooking appliance test methods are contained in 6.2 – 6.18.
Exception: Protection for tilt skillets is to be based upon the coverage limitations provided for deep fat fryer protection.
When tested with a cooking appliance, an extinguishing system unit shall:
- a) Result in the flame in the appliance to be completely extinguished upon complete discharge of the extinguishing agent;
- b) For deep fat fryers, woks, and ranges, not permit re-ignition of the grease for 20 minutes or until the temperature of the grease decreases at least 60°F (15°C) below its observed auto- ignition temperature, whichever is longer; and
- c) For all appliances other than deep fat fryers, woks- and ranges, not permit re-ignition of grease for 5 minutes.
Deep fat fryer
The deep fat fryer used for this test is to be a commercially available natural gas or propane fired deep fat fryer, at least 9 inches (229 mm) deep, and having a cooking surface area as specified in the manufacturer’s installation instructions. For a deep fat fryer with an integral drip board, or similar item, the calculated cooking area, along with the drip area, is to be as indicated in the manufacturer’s installation instructions.
All deep fat fryers tested in accordance with 6.2.1 and 6.2.3 – 6.2.8 shall demonstrate an average cooling rate of not more than 5°F (2.8°C) per minute. The liquid grease in an uncovered fryer is to be heated at the fryer’s maximum energy input. When the temperature of the liquid grease reaches 600°F (316°C) the fryer’s energy source is to be immediately shut off and the cooling rate of the liquid grease (°F per minute) is to be measured (when the temperature of the grease returns to 600°F (316°C)) between the temperatures of 600 and 500°F (316 and 260°C). The fryer is to be tested with an ambient temperature of 70 ±10°F (21 ±5°C) throughout the duration of the test. The thermocouple monitoring the liquid grease temperature is to be installed as indicated in 6.2.6.
Exception: When compliance with the deep fat fryer requirements is demonstrated using a specified cooling rate greater than 5°F (2.8°C) per minute, the protection of a deep fat fryer with a cooling rate exceeding 5°F (2.8°C) per minute is permitted. Fryers with a cooling rate exceeding 5°F (2.8°C) per minute shall be specifically indicated by model number in the manufacturer’s installation instructions.
Griddle
UL 300 Identical coverage and nozzle placement limitations for a griddle application are to be used based on a successful extinguishment test of a deep fat fryer. See 6.2.1 – 6.2.8.
The griddle used for this test is to be constructed of sheet metal at least 0.079 inch (2.01 mm) thick and is to be 1 inch (25.4 mm) deep.
Range top
UL 300The range top used for the test is to be a commercially available electric, natural gas or propane fired range top or a commercial range top burner to simulate variable range top configurations. When a manufacturer references protection for a range top incorporating a back shelf, a back shelf of the maximum size and located at the minimum height as specified in the manufacturers installation instructions is to be used for test. The cooking surfaces of the range top are to be the maximum as specified for coverage in the manufacturer’s installation, operation and maintenance instruction manual.
The following test vessels are to be used for this test:
a) A cast iron skillet having a diameter of 13 to 14 inches (330 to 356 mm) at the top and having sides 1-1/3 – 2-3/8 inches (33.9 – 60.3 mm) high, measured from the inside of the skillet.
b) A stainless steel pot having a diameter of 10 ±1/4 inches (254 ±6.4 mm) at the top and having sides 7 to 8 inches (178 to 203 mm) high.
Separate extinguishment tests are to be conducted using each test vessel.
Gas radiant char-broiler
UL 300 A commercially available gas radiant char-broiler or a char-broiler constructed to simulate a commercially available radiant broiler is to be used for this test. The char-broiler is to have a drip pan at least 1/2 inch (12.7 mm) deep located below the heating source. The char-broiler shall include a drip pan or equivalent solid bottom surface. The drip pan is to be filled with 1/8 inch (3.2 mm) of liquid grease. An extinguishing system unit is capable of being used with an electric char-broiler based on a successful extinguishment test using a gas radiant char-broiler, using identical coverage and nozzle placement limitations.
A thin plastic sheet, such as plastic food wrap, containing steaks and grease shall be placed on a flat surface at a location away from the char-broiler. The plastic sheet is to be covered with 1/4 inch (6.4 mm) of semisolid grease. Low-quality fatty beef steaks are then to be placed on top of the plastic sheet to cover an area equal to 80 – 90 percent of the char-broiler grate area.
Electric char-broiler
UL 300 A commercially available electric char-broiler or a char-broiler constructed to simulate a commercially available electric char-broiler is to be used for this test.
This test is to be conducted in the same manner as the gas radiant test specified in 6.5.1 – 6.5.4.
Lava, pumice, or synthetic rock char-broiler
Identical coverage and nozzle placement limitations for lava rock, pumice stone, or synthetic rock type char-broiler is to be used based on a successful extinguishment test of a lava rock type char-broiler. A gas or electrically heated char-broiler is to be used, and an extinguishing system unit is capable of being used with either heat source based on a successful extinguishment test using either heat source.
Natural charcoal broiler
UL 300 A commercially available charcoal broiler or a charcoal broiler constructed to simulate a commercially available charcoal broiler is to be used for this test. The char-broiler shall include a drip pan or equivalent solid bottom surface.
A thin plastic sheet, such as plastic food wrap, containing steaks and grease be placed on a flat surface at a location away from the charcoal broiler. The plastic sheet is to be covered with 1/4 inch (6.4 mm) of semisolid grease. Low-quality fatty beef steaks are then to be placed on top of the plastic sheet to cover an area equal to 80 – 90 percent of the cooking grate area.
UL 300 Mesquite wood char-broiler
A commercially available mesquite wood char-broiler or a mesquite wood char-broiler constructed to simulate a commercially available broiler is to be used for this test. The char-broiler shall include a drip pan or equivalent solid bottom surface. The test is to be conducted using the type of mesquite wood that is intended to be used with the char-broiler.
Upright broiler
UL 300 A commercially available upright broiler or an upright broiler constructed to simulate a commercially available upright broiler is to be used for this test. The broiling chamber is to be located at or about the midheight of the broiler and is to incorporate a broiling grate. A drip pan is to be placed directly below the broiler chamber. The bottom of the broiling chamber is to slope downward towards the drip pan and have an opening to allow the drainage of the grease from the broiling chamber. The broiler is also to incorporate a completely enclosed warming chamber directly above the broiling chamber. The broiling chamber is to be connected by internal passages to the top of the broiler to provide for exhaustion of grease laden vapors. The broiler is to incorporate a grease trap.
Chain broiler
A commercially available chain broiler or a chain broiler constructed to simulate a commercially available chain broiler is to be used for this test. The bottom of the broiling chamber is to slope downward toward a drip pan and have an opening to allow the drainage of the grease from the broiler chamber.
6.11.2 The drip pan below the broiler chamber is to be filled with preheated grease. The inner surfaces of the broiler chamber, cooking portion, and grease trap are to be coated with liquid grease to obtain a minimum loading of 0.3 pounds grease per square foot (1.5 kg/m2). Grease is also to be sprayed on all areas of the chain by causing the chain to rotate. When this is completed, 80 to 90 percent of the chain’s cooking area is to be covered with fatty hamburgers (that is, meat that is 70 percent lean) and the chain rotation stopped.
Upon complete discharge of the extinguishing agent, the chain broiler shall comply with the requirements in 6.1.2.
Wok
The minimum and maximum wok sizes specified in the manufacturer’s installation, operation, and maintenance instruction manual are to be tested. The wok sizes are to be determined by the minimum and maximum height and diameter.
UL 300 the heating source used for the tests is to be a commercially available electric, natural gas, or propane fired range top.
Deep fat fryer extinguishment splash test
When tested as described in 6.13.2 – 6.13.6, an extinguishing system unit shall:
- a) Result in the fire in a deep fat fryer to be completely extinguished; and
- b) Result in no splashing of burning grease due to the extinguishing system unit operation, as evidenced by the presence of burning droplets of grease dispersed outside the fryer.
The deep fat fryer used for this test is to be as specified in 6.2.1.
The test is to be conducted using the maximum discharge rate condition for the test nozzle or nozzles. The maximum discharge rate condition is obtained by using the maximum piping diameter, minimum piping length, and minimum number of tees and elbows, with the cylinder or gas cartridge conditioned to the maximum operating temperature for which the extinguishing system unit is intended.
Deep fat fryer cooking temperature splash test
When tested as described in 6.14.2 – 6.14.6, an extinguishing system unit shall not splash grease droplets in excess of 3/16 inch (4.76 mm) diameter.
The deep fat fryer used for this test is to be as specified in 6.2.1.
The test is to be conducted using the maximum discharge rate condition for the test nozzle or nozzles. The maximum discharge rate condition is obtained by using the maximum piping diameter, minimum piping length and minimum number of tees and elbows, with the cylinder or gas cartridge conditioned to the maximum operating temperature for at least 16 hours or pressurized to the maximum pressure corresponding to the maximum operating temperature for which the extinguishing system unit is intended.
Range top cooking temperature splash test
When tested as described in 6.16.2 – 6.16.4, an extinguishing system unit shall not splash grease droplets in excess of 3/16 inch (4.76 mm) diameter.
6.16.2 The test requirements specified in 6.15.2, 6.15.3 and 6.15.5 are to be used for this test.
6.16.3 The cast iron skillet is to be filled with liquid grease until the grease level is 1 inch (25.4 mm) below the edge of the skillet. The grease level is to be measured when the grease temperature is 350 – 375°F (177 – 191°C).
Wok extinguishment splash test
When tested as described in 6.17.2 – 6.17.6, an extinguishing system unit shall:
- a) Result in the fire in a wok to be completely extinguished; and
- b) Result in no splashing of burning grease due to the extinguishing system unit operation, as evidenced by the presence of burning droplets of grease dispersed outside the wok.
UL 300 the woks used for this test are to be as specified in 6.12.1.
The test is to be conducted using the maximum discharge rate condition for the test nozzle or nozzles. The maximum discharge rate condition is obtained by using the maximum piping diameter, minimum piping length and minimum number of tees and elbows, with the cylinder or gas cartridge conditioned to the maximum operating temperature for at least 16 hours or pressurized to the maximum pressure corresponding to the maximum operating temperature for which the extinguishing system unit is intended.
When tested as described in 6.18.2 – 6.18.6, an extinguishing system unit shall not splash grease droplets in excess of 3/16 inch (4.76 mm) diameter.
The woks used for this test are to be as specified in 6.12.1.
The test is to be conducted using the maximum discharge rate condition for the test nozzle or nozzles. The maximum discharge rate condition is obtained by using the maximum piping diameter, minimum piping length and minimum number of tees and elbows, with the cylinder or gas cartridge conditioned to the maximum operating temperature for at least 16 hours or pressurized to the maximum pressure corresponding to the maximum operating temperature for which the extinguishing system unit is intended.
An extinguishing system unit intended to protect the hood and duct of a restaurant cooking area shall be tested as described below.
Hood
The hood dimensions are to be the maximum as specified in the installation instructions. See 7.2.2 and 7.2.3, and Figure 7.1.
The hood is to be at least 4 feet (1.2 m) wide, increasing in increments of 1 foot (0.3 m) only.
The hood is to be 4, 6, 8, 10, 12, 16, 20, or 24 feet (1.2, 1.8, 2.4, 3.0, 3.7, 4.9, 6.1, or 7.3 m) long, or longer than 24 feet (7.3 m) in increments of 6 feet (1.8 m) only.
The hood is to be constructed of sheet steel having a minimum thickness of 0.079 inch (2.01 mm). 7.3 Filter and frame
Duct
The duct is to be rectangular or round, and an extinguishing system unit tested using a rectangular duct is capable of being used with a round duct having a circumference equal to or less than the perimeter of the rectangular duct. An extinguishing system unit to be used with round ducts only is to be tested using a round duct only. See Figure 7.1.
The duct perimeter is to be the maximum as specified in the installation instructions. See 7.4.4.
UL 300 the perimeter of a rectangular duct is to be 50 or less, 75, 100, 125, 150, or 300 inches (1.24, 1.90, 2.54, 3.17, 3.81, or 7.62 m) or larger. The diameter of a circular duct is to be 24, 32, 40, 48, or 95 inches (0.61, 0.81, 1.02, 1.22, or 2.4 m) or larger. A rectangular duct is to be installed with the longest side horizontal and the ratio between vertical and horizontal is to be 1:2, plus or minus 10 percent.
Extinguishing system unit preparation
Representative samples of extinguishing system units are to be subjected to the tests specified in
Hood and duct extinguishment are to be conducted using the minimum discharge rate condition for the test nozzles.
To obtain the minimum discharge rate condition, an extinguishing system unit is to be assembled using its maximum piping limitations with respect to number of fittings and size and length of pipe. The cylinder is to be filled to its rated capacity and the cylinder or gas cartridge pressurized with the expellant gas to the normal operating pressure at 70°F (21°C). The cylinder or gas cartridge used for these tests is to be conditioned, after charging, for at least 16 hours at the minimum storage temperature prior to the test. As an alternative to conditioning at the minimum storage temperature for 16 hours, extinguishing system units that utilize dry nitrogen or dry air as an expellant gas are to be tested by under pressurizing the cylinder or gas cartridge at ambient temperature to simulate the minimum operating temperature.
General test procedures
An extinguishing system unit intended for use with hood and duct systems is to be tested as described in 7.6.2 – 7.13.2. Additional test methods for specific cooking appliances are specified in cooking appliance extinguishment tests, 6.1.1 – 6.13.7.
Hood and duct (full scale) testing is to be conducted utilizing a commercially available or fabricated deep fat fryer constructed of sheet metal at least 0.079 inch (2.01 mm) thick, and at least 9 inches (229 mm) deep.
Fuel loading
The test fuel grease is to be heated until liquified and poured into a device required for uniformly coating the inside surfaces of the duct and plenum chamber such as a 2-1/2 gallon (9.5 L) stored pressure water-type extinguisher pressurized in the normal manner. When an extinguisher is used, a discharge assembly other than that provided with the extinguisher is capable of being used to provide for a spray discharge. The interior surfaces of the duct and plenum chamber are to be evenly coated with the grease to obtain a minimum loading of 0.3 pounds per square foot (1.5 kg/m2). Additional grease is capable of being used, particularly on large size ducts, to obtain the required sustained fire. See
Temperature measurement
7.8.1 The interior of the duct is to be provided with thermocouples located 12 and 20 feet (3.6 and 6.1 m) from the duct entrance. The thermocouples are to be Type K (chromel-alumel) of 18 or 20 AWG (0.82 or 0.52 mm2) wire with an untwisted welded bare bead junction not more than 0.050 inch (1.27 mm) in diameter. The thermocouples are to be located at the center of the cross section of the duct and are to be connected to chart recorders or other equivalent means for monitoring thermocouple temperatures.
Deep fat fryer
7.9.1 Each full scale fire test is to be conducted with a deep fat fryer located under the hood and directly below the duct entrance. The distance between the deep fat fryer and the hood entrance is to be as convenient for the test installation. The deep fat fryer is to be fully involved in flames prior to the 30 second countdown specified in 7.11.3.
Duct air flow
7.10.1 Tests are to be conducted at the following airflow/damper conditions:
- a) Duct outlet open at all times with no exhaust blower assistance permitted after ignition. See 7.11.2.
- b) UL 300 Duct outlet closed by the damper immediately before system actuation, with no exhaust blower assistance permitted after system actuation.
- c) 500 to 1000 feet per minute (152 to 305 m/min) velocity in duct, achieved by using exhaust blower assistance. The air flow in the duct is to be adjusted after ungreased filters are installed to obtain the appropriate discharge rate as specified below. Instruments, such as velometers or piezometers, are to be used for checking the air velocity and making the adjustments. A minimum of 9 measurement points are to be averaged to determine the velocity in the duct. The measurements are to be taken downstream of the hood and determined by dividing the cross section of the duct into 16 equal subsections. The measuring device is to be located at the point of intersection of the boundaries forming each subsection. An alternative means for measuring velocity is to be used when judged to provide equivalent results. The duct outlet shall remain open throughout the test.
Fuel ignition and extinguishing system unit operation
The ignition of the fire in the fryer, hood, and duct is to be initiated by external heat sources. Gas burners, propane burners, hand held propane torches, or similar items are sources of ignition. Previous testing has indicated that external heating sources applied under the hood and generating a heat output between 15,000 and 20,000 Btu (15,825 and 21,100 kJ) per minute is capable of igniting the hood area and duct. The ignition of the grease in the deep fat fryer is to be made using the fryer’s integral or an external heating source. Flammable liquids such as diesel fuel or gasoline are not to be used as ignition sources for the hood and duct.
UL 300 Ignition occurs when the temperature at the 12 foot (3.6 m) thermocouple reaches at least 1600°F (871°C) or when the temperature at the 20 foot (6.1 m) thermocouple reaches at least 1200°F (649°C), whichever occurs first. See 7.8.1. In general, the 12 foot (3.6 m) thermocouple reading fluctuates between 800 and 900°F (427 and 482°C) for a short while and then rise rapidly.
Plenum testing
In addition to the tests specified in 7.6.1 – 7.11.4, a plenum test is to be conducted with ignition occurring when the plenum and filter fire is at its maximum intensity, as determined by visual observation. At the point of maximum intensity, the system is to be manually actuated. Small residual flames shall self-extinguish. For the plenum test, the duct outlet is to be open and blower assistance as specified in 7.10.1(c) is to be used.
Prior to conducting the extinguishment test, discharge tests are to be conducted in the plenum area, using the air flows specified in 7.10.1 (a) and (c), to verify that the extinguishing agent is capable of covering the filter area.
Conditions of acceptability
UL 300 Upon actuation, the fire shall be extinguished as evidenced by a sharp decrease in temperature and in no instance shall an increase in any temperature occur. Routine fluctuations in recording instruments are to be disregarded. Small residual flames shall self-extinguish with no additional application of extinguishing agent.
The duct and hood are then to be examined after the fire has been extinguished. For successful test results, grease shall be present in the system to the extent that the grease was capable of sustaining the fire had it not been extinguished.
