In December 2017, the state of Ohio adopted it’s new “Fire Code” which happens to be a revised version of the 2015 International Fire Code. In November I posted a “heads-up” article about the “proposed” changes to new AMMONIA REFRIGERATION processes built in Ohio after 12/15/2017 and how their relief system(s) will be allowed to discharge. That posting got a lot of comments and debate as this conflicts with the ANSI/IIAR 2 – Standard for Safe Design of Closed-Circuit Ammonia Refrigeration Systems (2014). However, the state of Ohio saw fit to require ALL refrigeration processes that contain more than 6.6 pounds of NH3 to meet their newly adopted code. The state code does PERMIT “a variance” of sorts to their requirements as I laid out in the November 2017 article (SAFTENG Members can see it HERE). Here are the state’s new requirements, as of 12/15/2017… (emphasis and tiering of the requirements are by me)
NOTE: the content below is FREE (minus the links, explanations, and notations) on the State of Ohio Website for those who are not SAFTENG members.
NOTE 2: I have contacted the State Fire Marshal’s office regarding a couple of conflicts between the new Fire Code Section 606 and the state’s Mechanical Code as it relates to ammonia refrigeration. As soon as I hear back from this I will UPDATE this posting. UPDATED on 2/21/2018 with the response from OFM…
Hi Bryan,
Thanks for contacting me with your question…this one has caused me to do some homework to hopefully get you the answer you are looking for! When codes seem to conflict with each other, the more restrictive (or more protective to the public) code will usually take precedence and be effective for the situation at hand.
In regards to the requirements of the Ohio Fire Code Section 606.12.5, it does allow for the relief valves to be discharged directly to the atmosphere as long as there is documented testing that proves a fire, health or environmental hazard would not result from this discharge. While Section 1105.8 of the Ohio Mechanical Code refers to ASHRAE 15 for ammonia discharge, which allows untreated discharge, the Fire Code section is more restrictive in that it requires that the discharge be treated in an approved manner or for it to be proven to show that the release would pose no danger to people or property. I do not currently have a copy of the Commentary for the 2015 IFC, but I checked the 2009 IFC and while the wording has been updated and rearranged, it appears the intent of the code has remained unchanged. Below is some information quoted from the Commentary Section of the 2009 IFC that may help explain the situation better:
“This section [of the Fire Code] parallels Section 1105.8 of the International Mechanical Code, which references ASHRAE 15. In addition to incineration and absorption in water, ASHRAE 15 allows direct discharge to the atmosphere at prescribed distances above grade and from building openings.”
“There are some cases, such as at remote facilities, where atmospheric discharge of ammonia would pose no danger to people or property and provides a basis in the code for permitting relief lines on ammonia refrigeration systems to discharge to the atmosphere when an appropriate analysis has been performed and accepted by the fire code official to show that such discharge can be accomplished safely. In such cases, a flaring or water diffusion system would serve no beneficial purpose, since ammonia is naturally biodegradable… [This] also provides correlation with the additional flexibility that is already available in the International Mechanical Code, while maintaining the fire code official’s authority under the code to accept or reject any proposal.”
Source: 2009 International Fire Code Commentary, International Code Council
In looking at the termination requirements of the Ohio Mechanical Code (Section 1105.7 below), I believe the relief valves could be discharged to the atmosphere as long as the relief devices terminated in the proper location and there were testing results available to show that a fire, health or environmental hazard would not result from atmospheric discharge of ammonia.
2017 Ohio Mechanical Code
Section 1105.7 Termination of relief devices.Pressure relief devices, fusible plugs and purge systems located within the machinery room shall terminate outside of the structure at a location 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.
2017 Ohio Mechanical Code
Section 1105.8 Ammonia discharge. Pressure relief valves for ammonia systems shall discharge in accordance with ASHRAE 15.
So long story short, I believe you could discharge the relief valves to the atmosphere as long as you have met the proper location requirements for the termination of the valves and there was supporting documentation that proves it will not cause fire, health or environmental hazard by doing so. Of course, all of this is also dependent upon approval from the Building Code Official for the installation of the equipment. Plan review from their office would be a deciding factor as well.
I hope this information proves helpful to you. Please let me know if I can help further.
Thank you,
Jason
Jason Corwin
Southwest District Chief / Assistant Chief
Ohio Department of Commerce
Division of State Fire Marshal, Code Enforcement Bureau
8895 E. Main Street, Reynoldsburg, Ohio, 43068
Direct Line: 614.361.9542 Code Enforcement Bureau: 614.728.5460
Scheduling: 614.644.5574
[email protected] www.com.ohio.gov/fire
This message and any response to it may constitute a public record and thus may be publicly available to anyone who requests it.
Section 606 Mechanical Refrigeration
606.1 Scope
Refrigeration systems shall be installed in accordance with the mechanical code as listed in rule 1301:7-7-80 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 1301:7-7-80 of the Administrative Code.
606.3 Refrigerant classification
Refrigerants shall be classified in accordance with the mechanical code as listed in rule 1301:7-7-80 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 1301:7-7-80 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 606.6.1 of this rule.
Records of tests shall be maintained.
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.
- 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 1301:7-7-80 of the Administrative Code.
Hazard signs shall be in accordance with the mechanical code as listed in rule 1301:7-7-80 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 1301:7-7-80 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
Where flammable refrigerants are used and compliance with section 1106 of the mechanical code as listed in rule 1301:7-7-80 of the Administrative Code is required, remote control of the mechanical equipment and appliances located in the machinery room as required by paragraphs 606.9.1 and 606.9.2 of this rule 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 when 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.
606.9.2 Ventilation system
A clearly identified switch of the break-glass type or with an approved tamper-resistant cover shall provide ON-ONLY control of the machinery room ventilation fans.
606.10 Emergency pressure control system
PERMANENTLY INSTALLED 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 606.10.1 and 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
Where 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 set point 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 1301:7-7-50, rule 1301:7-7-53, rule 1301:7-7-55 and rule 1301:7-7-57 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 Discharge and termination of pressure relief and purge systems
Pressure relief devices, fusible plugs and purge systems discharging to the atmosphere from refrigeration systems containing more than 6.6 pounds (3 kg) of flammable, toxic or highly toxic refrigerants or ammonia shall comply with paragraphs 606.12.3 to 606.12.5 of this rule.
606.12.1 Standards
Refrigeration systems and the buildings in which such systems are installed shall be in accordance with ASHRAE 15 as listed in rule 1301:7-7-80 of the Administrative Code.
606.12.1.1 Ammonia refrigeration
Refrigeration systems using ammonia refrigerant and the buildings in which such systems are installed shall comply with IIAR-2 as listed in rule 1301:7-7-80 of the Administrative Code for system design and installation and IIAR-7 as listed in rule 1301:7-7-80 of the Administrative Code for operating procedures.
606.12.2 Fusible plugs and rupture members
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 the fusible plug or rupture member functions.
606.12.3 Flammable refrigerants
Systems containing more than 6.6 pounds (3 kg) of 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 606.12.6 of this rule or a flaring system in accordance with paragraph 606.12.7 of this rule.
Systems containing more than 6.6 pounds (3 kg) of flammable refrigerants having a density 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.
606.12.4 Toxic and highly toxic refrigerants
Systems containing more than 6.6 pounds (3 kg) of toxic or highly toxic refrigerants shall discharge vapor to the atmosphere only through an approved treatment system in accordance with paragraph 606.12.6 of this rule or a flaring system in accordance with paragraph 606.12.7 of this rule.
606.12.5 Ammonia refrigerant
Systems containing MORE THAN 6.6 pounds (3 kg) of ammonia refrigerant shall discharge vapor to the atmosphere in accordance with one of the following methods:
-
- Directly to atmosphere where the fire code official determines, on review of an engineering analysis prepared in accordance with paragraph 104.7.2 of rule 1301:7-7-01 of the Administrative Code, that a fire, health or environmental hazard would NOT result from atmospheric discharge of ammonia.
- Through an approved treatment system in accordance with paragraph 606.12.6 of this rule.
- Through a flaring system in accordance with paragraph 606.12.7 of this rule.
- Through an approved ammonia diffusion system in accordance with paragraph 606.12.8 of this rule.
- By other approved means.
Exception: Ammonia/water absorption systems containing less than 22 pounds (10 kg) of ammonia AND for which the ammonia circuit is located ENTIRELY OUTDOORS.
606.12.6 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 1301:7-7-60 of the Administrative Code.
606.12.7 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.
Standby electrical power, where required to complete the incineration process, shall be in accordance with paragraph 604 of this rule.
606.12.8 Ammonia diffusion systems
Ammonia diffusion systems shall include a tank containing 1 gallon of water for each pound of ammonia (8.3 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 5003.3.1 of rule 1301:7-7-50 of the Administrative Code.
606.15 Records
A record of refrigerant quantities BROUGHT INTO AND REMOVED from the premises shall be maintained.
606.16 Electrical equipment
Where refrigerants of Groups A2, A3, B2 and B3, as defined in the mechanical code as listed in rule 1301:7-7-80 of 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 1301:7-7-80 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 rule 1301:7-7-80 of the Administrative Code.
Source: OH Fire Code, Chapter 6