I have highlighted some surprises for those of you in OH that may be reading this! FYI, Anhydrous Ammonia is a Group B2 refrigerant, based on Addenda to Designation and Safety Classifications of Refrigerants. Be sure to click on the Links to the other applicable OH Fire Codes referenced in this section!
Chapter 1301:7-7 Ohio Fire Code
1301:7-7-06 Building services and systems
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(F) Section 606 Mechanical refrigeration
606.1 Scope. Refrigeration systems shall be installed in accordance with the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code.
606.2 Refrigerants. The use and purity of new, recovered and reclaimed refrigerants shall be in accordance with the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code.
606.3 Refrigerant classification. Refrigerants shall be classified in accordance with the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code.
606.4 Change in refrigerant type. A change in the type of refrigerant in a refrigeration system shall be in accordance with the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code.
606.5 Access. Refrigeration systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant shall be accessible to the fire department at all times as required by the fire code official.
606.6 Testing of equipment. Refrigeration equipment and systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant shall be subject to periodic testing in accordance with paragraph (F)(6)(a)(606.6.1) of this rule. A written record of required testing shall be maintained on the premises. Tests of emergency devices or systems required by this rule shall be conducted by persons trained and qualified in refrigeration systems.
606.6.1 Periodic testing. The following emergency devices or systems shall be periodically tested in accordance with the manufacturer’s instructions and as required by the fire code official.
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- Treatment and flaring systems.
- Valves and appurtenances necessary to the operation of emergency refrigeration control boxes.
- Fans and associated equipment intended to operate emergency ventilation systems.
- Detection and alarm systems.
606.7 Emergency signs. Refrigeration units or systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant shall be provided with approved emergency signs, charts and labels in accordance with NFPA 704 as listed in rule 1301:7-7-47 of the Administrative Code. Hazard signs shall be in accordance with the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code for the classification of refrigerants listed therein.
606.8 Refrigerant detector. Machinery rooms shall contain a refrigerant detector with an audible and visual alarm. The detector, or a sampling tube that draws air to the detector, shall be located in an area where refrigerant from a leak will concentrate. The alarm shall be actuated at a value not greater than the corresponding TLV-TWA values shown in the mechanical code as listed in rule 1301:7-7-47 of the Administrative Code for the refrigerant classification. Detectors and alarms shall be placed in approved locations. The detector shall transmit a signal to an approved location.
606.9 Remote controls. Remote control of the mechanical equipment and appliances located in the machinery room shall be provided at an approved location immediately outside the machinery room and adjacent to its principal entrance.
606.9.1 Refrigeration system emergency shutoff. A clearly identified switch of the break-glass type or with an approved tamper-resistant cover shall provide off-only control of refrigerant compressors, refrigerant pumps and normally closed automatic refrigerant valves located in the machinery room. Additionally, this equipment shall be automatically shut off whenever the refrigerant vapor concentration in the machinery room exceeds the vapor detector’s upper detection limit or 25 per cent of the LEL, whichever is lower.
Exception: In machinery rooms where only nonflammable refrigerants are used, only compressors are required to be stopped by vapor detection or the cut-off switch.
606.9.2 Ventilation system. A clearly identified switch of the break-glass type shall provide on-only control of the machinery room ventilation fans.
606.10 Emergency pressure control system. Refrigeration systems containing more than 6.6 pounds (3 kg) of flammable, toxic or highly toxic refrigerant or ammonia shall be provided with an emergency pressure control system in accordance with paragraphs (F)(10)(a)(606.10.1) and (F)(10)(b)(606.10.2) of this rule.
606.10.1 Automatic crossover valves. Each high- and intermediate-pressure zone in a refrigeration system shall be provided with a single automatic valve providing a crossover connection to a lower pressure zone. Automatic crossover valves shall comply with paragraphs (606.10.1.1) to (606.10.1.3) of this rule.
606.10.1.1 Overpressure limit set point. Automatic crossover valves shall be arranged to automatically relieve excess system pressure to a lower pressure zone if the pressure in a high- or intermediate-pressure zone rises to within 90 per cent of the set point for emergency pressure relief devices.
606.10.1.2 Manual operation. When required by the fire code official, automatic crossover valves shall be capable of manual operation.
606.10.1.3 System design pressure. Refrigeration system zones that are connected to a higher pressure zone by an automatic crossover valve shall be designed to safely contain the maximum pressure that can be achieved by interconnection of the two zones.
606.10.2 Automatic emergency stop. An automatic emergency stop feature shall be provided in accordance with paragraphs (606.10.2.1) and (606.10.2.2) of this rule.
606.10.2.1 Operation of an automatic crossover valve. Operation of an automatic crossover valve shall cause all compressors on the affected system to immediately stop. Dedicated pressure-sensing devices located immediately adjacent to crossover valves shall be permitted as a means for determining operation of a valve. To ensure that the automatic crossover valve system provides a redundant means of stopping compressors in an overpressure condition, high-pressure cutout sensors associated with compressors shall not be used as a basis for determining operation of a crossover valve.
606.10.2.2 Overpressure in low-pressure zone. The lowest pressure zone in a refrigeration system shall be provided with a dedicated means of determining a rise in system pressure to within 90 per cent of the setpoint for emergency pressure relief devices. Activation of the overpressure sensing device shall cause all compressors on the affected system to immediately stop.
606.11 Storage, use and handling. Flammable and combustible materials shall not be stored in machinery rooms for refrigeration systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant. Storage, use or handling of extra refrigerant or refrigerant oils shall be as required by rule 1301:7-7-27, rule 1301:7-7-30, rule 1301:7-7-32 and rule 1301:7-7-34 of the Administrative Code.
Exception: This provision shall not apply to spare parts, tools and incidental materials necessary for the safe and proper operation and maintenance of the system.
606.12 Termination of relief devices. Pressure relief devices, fusible plugs and purge systems for refrigeration systems containing more than 6.6 pounds (3 kg) of flammable, toxic or highly toxic refrigerants shall be provided with an approved discharge system as required by paragraphs (606.12.1), (606.12.2) and (606.12.3) of this rule. Discharge piping and devices connected to the discharge side of a fusible plug or rupture member shall have provisions to prevent plugging the pipe in the event of the fusible plug or rupture member functions.
606.12.1 Flammable refrigerants. Systems containing flammable refrigerants having a density equal to or greater than the density of air shall discharge vapor to the atmosphere only through an approved treatment system in accordance with paragraph (F)(12)(d)(606.12.4) of this rule or a flaring system in accordance with paragraph (F)(12)(e)(606.12.5) of this rule. Systems containing flammable refrigerants having a density of less than the density of air shall be permitted to discharge vapor to the atmosphere provided that the point of discharge is located outside of the structure at not less than 15 feet (4572 mm) above the adjoining grade level and not less than 20 feet (6096 mm) from any window, ventilation opening or exit.
606.12.2 Toxic and highly toxic refrigerants. Systems containing toxic or highly toxic refrigerants shall discharge vapor to the atmosphere only through an approved treatment system in accordance with paragraph (F)(12)(d)(606.12.4) of this rule or a flaring system in accordance with paragraph (F)(12)(e)(606.12.5) of this rule.
606.12.3 Ammonia refrigerant. Systems containing ammonia refrigerant shall discharge vapor to the atmosphere through an approved treatment system in accordance with paragraph (F)(12)(d)(606.12.4) of this rule, a flaring system in accordance with paragraph (F)(12)(e)(606.12.5) of this rule, or through an approved ammonia diffusion system in accordance with paragraph (F)(12)(f)(606.12.6) of this rule, or by other approved means.
Exceptions:
1. Ammonia/water absorption systems containing less than 22 pounds (10 kg) of ammonia and for which the ammonia circuit is located entirely outdoors.
2. When the fire code official determines, on review of an engineering analysis prepared in accordance with paragraph (D)(7)(b)(104.7.2) of rule1301:7-7-01 of the Administrative Code, that a fire, health or environmental hazard would not result from discharging ammonia directly to the atmosphere.
606.12.4 Treatment systems. Treatment systems shall be designed to reduce the allowable discharge concentration of the refrigerant gas to not more than 50 per cent of the IDLH at the point of exhaust. Treatment systems shall be in accordance with rule 1301:7-7-37 of the Administrative Code.
606.12.5 Flaring systems. Flaring systems for incineration of flammable refrigerants shall be designed to incinerate the entire discharge. The products of refrigerant incineration shall not pose health or environmental hazards. Incineration shall be automatic upon initiation of discharge, shall be designed to prevent blowback and shall not expose structures or materials to threat of fire. Standby fuel, such as LP gas, and standby power shall have the capacity to operate for one and one-half the required time for complete incineration of refrigerant in the system.
606.12.6 Ammonia diffusion systems. Ammonia diffusion systems shall include a tank containing 1 gallon of water for each pound of ammonia (4 L of water for each 1 kg of ammonia) that will be released in 1 hour from the largest relief device connected to the discharge pipe. The water shall be prevented from freezing. The discharge pipe from the pressure relief device shall distribute ammonia in the bottom of the tank, but no lower than 33 feet (10 058 mm) below the maximum liquid level. The tank shall contain the volume of water and ammonia without overflowing.
606.13 Discharge location for refrigeration machinery room ventilation. Exhaust from mechanical ventilation systems serving refrigeration machinery rooms containing flammable, toxic or highly toxic refrigerants, other than ammonia, capable of exceeding 25 per cent of the LFL or 50 per cent of the IDLH shall be equipped with approved treatment systems to reduce the discharge concentrations to those values or lower.
606.14 Notification of refrigerant discharges. The fire code official shall be notified immediately when a discharge becomes reportable under state, federal or local regulations in accordance with paragraph (C)(3)(a)(2703.3.1) of rule 1301:7-7-27 of the Administrative Code.
606.15 Records. A written record shall be kept of refrigerant quantities brought into and removed from the premises. Such records shall be available to the fire code official.
606.16 Electrical equipment. Where refrigerants of Groups A2, A3, B2 and B3, as defined in the mechanical code as listed in rule 1301:7-7-47of the Administrative Code, are used, refrigeration machinery rooms shall conform to the Class I, Division 2 hazardous location classification requirements of NFPA 70 as listed in rule 1301:7-7-47 of the Administrative Code.
Exception: Ammonia machinery rooms that are provided with ventilation in accordance with section 1106.3 of the mechanical code as listed in rule1301:7-7-47 of the Administrative Code.