Wet Chemical Kitchen System Expansion
A restaurant has an existing wet chemical system under a 12-foot hood. The cylinder is a 1.5-gallon unit with a listed configuration for one fryer and one range, plus a plenum nozzle and a duct nozzle. The owner now adds a 4-burner range and a salamander broiler under the same hood, bringing the cooking line to four appliances. The appliance nozzles were not changed, and the new range extends 8 inches past the hood's end. The gas shutoff is a manual ball valve with no automatic linkage. The fusible link is installed 22 inches above the cooking surface, and the manual pull station is 14 feet from the hood. The owner wants the contractor to 'just add another nozzle and use the same cylinder' to avoid replacing the system.
1. Can the existing system be extended by adding a nozzle to the same cylinder? Explain what must be verified.
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No. A wet chemical system is a listed assembly: the cylinder size, piping, nozzle flow, and appliance coverage are part of the listing. Adding a nozzle changes flow and agent distribution, and the 1.5-gallon cylinder may not have capacity for four appliances. Verify the manufacturer's listed design for each appliance, cylinder capacity, pipe sizes, nozzle spacing and height, and hood, plenum, and duct coverage. If the new range and salamander are not in the listed configuration, submit a revised design or replace the system. The correct judgment is that field modification cannot be approved merely by adding a nozzle; the listed design must be re-established by the manufacturer or engineer.
2. List the deficiencies beyond nozzle count and the corrections required.
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The 8-inch extension past the hood means the new range is not fully under the hood; extend the hood or relocate the appliance. The fusible link at 22 inches must be checked against the listed height; if it is outside the listing, relocate it. The manual pull station must be in the path of egress and accessible; verify its location against the listing. Most importantly, the gas shutoff must be automatic and linked to the system, not a manual ball valve. Add appliance-specific nozzles and covers, update the placard, verify cylinder weight and hydrostatic date, and confirm the correct cartridge and actuation method.
3. Describe the acceptance test and documentation after the modification.
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After modification, perform the manufacturer's acceptance flow test using water or the listed test method, verify that all nozzles discharge in the correct pattern and sequence, and confirm that the agent reaches each appliance, plenum, and duct. Test manual and automatic actuation, verify automatic gas and electric shutoff, replace fusible links, and check cylinder pressure and weight. Provide as-built drawings, the manufacturer's design calculation, the test report, and owner training. The AHJ should receive evidence that the installed system matches a listed configuration, not just that nozzles were added.