EDITOR’S NOTE:
Jeff Shapiro is president of International Code Consultants and serves as IIAR’s code consultant. This article is the first in a two-part series examining 2018 and 2021 codes and the future of code development.

The 2018 editions of the International, Uniform and NFPA codes that affect the ammonia refrigeration industry, including the International Mechanical Code (IMC), International Fire Code (IFC), International Building Code (IBC), Uniform Mechanical Code (UMC) and NFPA Fire Code (NFPA 1) are now published and are pending adoption in many jurisdictions in the United States. There are a number of changes in these latest editions that are of interest to IIAR members, and this article summarizes those that are most significant. In addition, important changes to the 2017 edition of the National Electrical Code (NEC) and the latest Factory Mutual Data Sheets affecting ammonia refrigeration are discussed.

In Part 2, which will be published in the next Condenser, a preview of IIAR’s proposals to ASHRAE 15 and the 2021 model codes will be provided. These proposals are just beginning the code development processes for the various model codes.

Some changes in code text in this article are shown in “legislative format” to indicate deleted text (strike-out format) and new text (underline format) for clarity.

APPROVED PROPOSALS

This article outlines the significant changes affecting ammonia refrigeration that were approved for inclusion in the 2018 editions of the IMC, IFC, IBC, UMC and NFPA 1, and the 2017 edition of the NEC. All of these changes are considered as positive for the ammonia refrigeration industry.

2018 IMC

• Section 202 Definitions: MACHINERY ROOM. An enclosed space that is required by Chapter 11 to contain refrigeration equipment and to comply with Sections 1105 and 1106.

  Discussion: The definition of “Machinery Room” has been changed to clarify that spaces must only meet machinery room construction requirements when the machinery room is required by code. Spaces that contain equipment that does not trigger a machinery room requirement in Chapter 11 are now clearly NOT required to be constructed as machinery rooms simply because some ammonia related equipment happens to be present. This issue had sometimes been a point of contention with code officials in the past.

• Section 202 Definitions: LOW PROBABILITY PUMP. A pump that is designed to prevent atmospheric release of the pumped fluid in accordance with one of the following methods: 1. The pump is permanently sealed, 2. The pump incorporates a static seal, or 3. The pump incorporates not less than two sequential dynamic shaft seals to isolate the pumped fluid from atmosphere at shaft penetrations and automatically shuts down upon failure of any seal.

  Discussion: See Section 1104.2.2(6) below for how this definition applies. Also note that early printings of the 2018 IMC included a different definition, which is incorrect. The International Code Council, which publishes the IMC, has noted this as an errata issue, and future IMC printings will correct the definition with the text shown above.

• Section 1104.2.2 Industrial occupancies and refrigerated rooms: This section applies only to rooms and spaces that: are within industrial occupancies; contain a refrigerant evaporator; are maintained at temperatures below 68°F (20°C); and are used for manufacturing, food and beverage preparation, meat cutting, other processes and storage. Machinery rooms are Where a machinery room would otherwise be required by Section 1104.2, a machinery room shall not be required where all of the following conditions are met:

  Discussion: Section 1104.2.2 establishes a list of conditions that must all be satised to legally permit refrigeration equipment outside of a machinery room in industrial process and storage areas. Were it not for this exception, refrigerant concentration limits would force most direct evaporators and condensers on ammonia systems to be located in machinery rooms, which would essentially prevent the use of large, direct ammonia systems. In the 2018 edition, IIAR was successful in gaining approval of a modification to Section 1104.2.2 to clearly state that the conditions in this section ONLY apply to cases where a machinery room was otherwise required. This differs from the previous text, which triggered all of the conditions anytime that direct evaporators or condensers were not in a machinery room. The change opens the door for small charge systems to possibly be used in process and storage areas without having to comply with the listed conditions. Text extracts below show the conditions/numbered items under Section 1104.2.2 that were modified in the 2018 edition based on IIAR proposals. For the remaining conditions that are not shown here, see the IMC. 3.

• The floor area per occupant is not less than 100 square feet (9.3 m2) where machinery is located on floor levels with exits more than 6.6 feet (2012 mm) above the ground. Where provided with egress directly to the outdoors or into approved building exits, the minimum floor area shall not apply.

  Discussion: Item 3 in the 2015 and prior editions of the IMC has been deleted. The provision had implied that industrial process and storage areas had to be designed and occupied with a minimum occupant load density of 100 square feet per person. However, the requirement was essentially moot because the second sentence typically negated the first. Furthermore, there was no logical reason to mandate a minimum occupant density for refrigerated areas when no similar requirements existed for other industrial or hazardous occupancies. The section was apparently often overlooked, and deleting it gets rid of one more ambiguity that encumbers the design and operation of refrigerated process and storage areas.

  Refrigerant detectors are installed as required for machinery rooms in accordance with Section 1105.3.

Exceptions:

1. Refrigerant detectors are not required in unoccupied areas that contain only continuous piping that does not include valves, valve assemblies, equipment, or equipment connections.
2. Where approved alternatives are provided, refrigerant detectors for ammonia refrigeration are not required for rooms or areas that are always occupied, and for rooms or areas that have high humidity or other harsh environmental conditions that are incompatible with detection devices.

   Discussion: Item 3 in the 2018 edition (previously Item 4) has two new exceptions that were added to allow omission of refrigerant leak detection in areas where refrigeration equipment is located outside of a machinery room. The detection requirement in this item are seemingly not well-known, which may have resulted in some refrigerated process and storage areas not including required refrigerant leak detection equipment. Nevertheless, the blanket requirement that was in previous code editions was unreasonably restrictive or impractical for some situations, and IIAR was successful in gaining two new exceptions to the requirement.

   Leak detection is no longer required where: 1) A space is unoccupied and contains only continuous piping that does not include valves, valve assemblies, equipment, or equipment connections, such as pipe chases, and 2) Where approved alternatives are provided for rooms or areas that are always occupied, and for rooms or areas that have high humidity or other harsh environmental conditions that are incompatible with detection devices. Such alternatives might involve having an emergency plan that includes provisions for scheduled periodic rounds by authorized personnel to check for leaks and a protocol for reporting and responding to any release that may occur.

3.  All refrigerant-containing parts in systems with a total connected compressor power exceeding 100 horsepower (hp) (74.6 kW) drive power, except evaporators used for refrigeration or dehumidication, condensers used for heating, control and pressure relief valves for either, low-probability pumps and connecting piping, are located either outdoors or in a machinery room.

   Discussion: Item 6 lists the equipment that is allowed by Section 1104.2.2 to be outside of a machinery room. One change promoted by IIAR was clarifying that the 100 hp limit on equipment permitted outside of a machinery room applies to the total connected compressor power per system vs including other motor-driven equipment, such as condensers or liquid pumps.

   A second revision added provisions for “low probability pumps.” In addition to the previous allowance for evaporators, condensers and ancillary piping and valves, the IMC now allows low-probability pumps (as defined above to mean pumps that are constructed in such a way as to have a reliable means of preventing leakage of refrigerant to atmosphere) to be located outside of a machinery room in refrigerated industrial process and storage areas. This coordinates with provisions that were added to the 2014 edition of IIAR 2 and allows the use of low-probability liquid pumps in close proximity to evaporators. Pumps that are not low-probability are still permitted, but they must be enclosed in a space meeting the requirements for a machinery room.

• Section 1106.1 General: Refrigeration systems shall comply with the requirements of this code and, except as modified by this code, ASHRAE 15. Ammonia-refrigerating systems shall comply with this code and, except as modified by this code, ASHRAE 15 and IIAR 2, IIAR 3, IIAR 4 and IIAR 5.

  Discussion: IIAR 3, IIAR 4 and IIAR 5 have been adopted as official, enforceable reference standards.

2018 IFC

• Section 605.1 Scope: Refrigeration systems shall be installed in accordance with the International Mechanical Code.

  605.1.1 Refrigerants other than ammonia. Where a refrigerant other than ammonia is used, refrigeration systems and the buildings in which such systems are installed shall be in accordance with ASHRAE 15.

  605.1.2 Ammonia refrigeration. Refrigeration systems using ammonia refrigerant and the buildings in which such systems are installed shall comply with IIAR-2 for system design and installation and IIAR-7 for operating procedures. Decommissioning of ammonia refrigeration systems shall comply with IIAR-8.

  Discussion: This revision is part of IIAR’s ongoing effort to separate ammonia refrigeration from ASHRAE 15 and gain recognition of IIAR standards as a standalone basis for regulation of ammonia refrigeration systems. The firsrst step in this process, which has now been accomplished in the 2018 International Fire Code, is having codes reference ASHRAE 15 for refrigerants other than ammonia and only IIAR standards for ammonia systems.

• Section 605.8 Refrigerant detectorion. Machinery rooms shall be provided with a refrigerant 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 International Mechanical Code for the refrigerant classification. Detectors and alarms shall be placed in approved locations. The detector shall transmit a signal to an approved location with an audible and visible alarm. Where ammonia is used as the refrigerant, detection shall comply with IIAR 2. For refrigerants other than ammonia, refrigerant detection shall comply with Section 605.8.1.

  605.8.1 Refrigerants other than ammonia. A detector, or a sampling tube that draws air to a detector, shall be provided at an approved location where refrigerant from a leak is expected to accumulate. The system shall be designed to initiate audible and visible alarms inside of and outside each entrance to the refrigerating machinery room and transmit a signal to an approved location where the concentration of refrigerant detected exceeds the lesser of the following:

  1. The corresponding TLV-TWA values shown in the International Mechanical Code for the refrigerant Classification.
  2. Twenty-five percent of the lower flammable limit (LFL). Detection of a refrigerant concentration exceeding the upper detection limit or 25 percent of the lower flammable limit (LFL), whichever is lower, shall stop refrigerant equipment in the machinery room in accordance with Section 605.9.1.

  Discussion: The 2018 edition of the IFC includes a comprehensive rewrite of provisions for all gas detection systems. Among the revisions is a new Section 916 for this topic. Although refrigerant leak detection was included as part of this revision, ammonia refrigeration was granted a unique exemption from the new requirements because the 2014 edition of IIAR 2 provides comprehensive regulations for ammonia refrigerant leak detection systems. This exemption is embedded in IFC Section 605.8, which defers to IIAR 2.

2018 IBC

• Section 1006.2.2.2 Refrigeration Machinery Rooms: Machinery rooms larger than 1,000 square feet shall have not less than two exits or exit access doorways. Where two exit access doorways are required, one such doorway is permitted to be served by a fixed ladder or an alternating tread device. Exit access doorways shall be separated by a horizontal distance equal to one-half the maximum horizontal dimension of the room.

  All portions of machinery rooms shall be within 150 feet (45 720 mm) of an exit or exit access doorway. An increase in exit access travel distance is permitted in accordance with Section 1017.1.

  Doors Exit and exit access doorways shall swing in the direction of egress travel, regardless of the occupant load served. Doors Exit and exit access doorways shall be tight fitting and self-closing.

  Discussion: Machinery room door requirements have been changed to make it clear that ONLY those door that serve as a means of egress are required to swing outwards from the machinery room and be tight-fitting and self-closing. Previous IBC code text suggested that all doors leading out of a machinery room were required to swing in the outward direction, even if they led to a control room, electrical room or other space that was not part of the intended egress path.

  The provisions related to doors being tight-fitting and self-closing were also changed to only apply to exit and exit access doors. However, that change was essentially editorial and was only made because exit and exit access doors are the only door types regulated by IBC Section 1006. IIAR 2 will still require ALL machinery room doors be tight-fitting and self-closing. It is also important to remember that IIAR 2 requires exit and exit access doors to have panic hardware.

2018 UMC

• 1102.0 Refrigeration Systems.
  
  1102.1 General. Refrigeration systems using a refrigerant other than ammonia shall comply with this chapter and ASHRAE 15.

  1102.2 Ammonia Refrigeration Systems. Exception: Refrigeration systems using ammonia refrigeration systems as the refrigerant shall comply with IIAR 2, IIAR 3, IIAR 4, and IIAR 5 and shall not be required to comply with this chapter.

  Discussion: This revision is part of IIAR’s ongoing effort to separate ammonia refrigeration from ASHRAE 15 and gain recognition of IIAR standards as a standalone basis for regulation of ammonia refrigeration systems. The first step in this process, having codes reference ASHRAE 15 for refrigerants other than ammonia and only IIAR standards for ammonia systems, was completed in the 2015 UMC.

  The second step in this process, having codes entirely defer to IIAR standards for ammonia systems, was completed for the UMC in the 2018 edition. Based on the above change and several other revisions to UMC Chapter 11 that eliminated all references to ammonia refrigeration, UMC Chapter 11 no longer applies to ammonia refrigeration systems. Instead, the code now simply requires compliance with IIAR 2, 3, 4 and 5, recognizing that IIAR’s documents are comprehensive and no longer rely on codes or other standards for supplemental requirements.

  Note that IIAR’s other standards, which relate to system operation, maintenance and decommissioning, are not referenced by the UMC, but are instead referenced by fire codes. This is because the UMC is geared to new construction; whereas, fire codes include regulations for existing occupancies and equipment.

  The UMC’s complete deferral to IIAR ammonia refrigeration standards is the most significant acknowledgement to date of IIAR’s status as the leading standards development organization (SDO) representing the interest of the ammonia refrigeration industry.

2018 NFPA 1

• Sections 53.2.3.1.1 and 53.2.3.3.3:
  
  53.2.3.1.1 Alarm Threshold. The refrigerant vapor detector shall activate approved visual and audible alarm signaling devices at one of the following refrigerant thresholds:
  (1) At a value not greater than the corresponding TLV-TWA (or toxicity measure consistent therewith); not to exceed 25 percent of the lower flammable limit (LFL)
  (2) For ammonia, at a concentration not exceeding 1000 25 parts per million
  
  53.2.3.3.3 For systems using a refrigerant other than ammonia, pPurge fans shall also respond automatically to the refrigerant concentration detection system set to activate the ventilation system at the threshold levels set forth in 53.2.3.1.1. For systems using ammonia, purge fans shall also respond automatically to the refrigerant concentration detection system set to activate the ventilation system at an ammonia concentration not exceeding 150 parts per million.

  Discussion: These sections were revised to correlate the provisions for refrigerant detection alarm and emergency ventilation activation fan thresholds with IIAR 2, which specifies 25 ppm for alarms and 150 ppm for emergency ventilation. Previously, NFPA 1 specified 1,000 ppm for both, which created a conflict between the code and its IIAR reference standard.

• Section 53.3 Operations, Maintenance, and Testing, and Decommissioning.
  
  53.3.3 Decommissioning of Ammonia Refrigeration Systems.
  Decommissioning of closed-circuit ammonia refrigeration systems shall comply with ANSI/IIAR 8, Decommissioning of Closed-Circuit Ammonia Refrigeration Systems.

  Discussion: IIAR 8 has been adopted as official, enforceable reference standard.

2017 NEC (CLASSIFIED ELECTRICAL EQUIPMENT):

•  500.5(A) General. Locations shall be classified depending on the properties of the flammable gas, flammable liquid–produced vapor, combustible liquid–produced vapors, combustible dusts, or fibers/flyings that could be present, and the likelihood that a flammable or combustible concentration or quantity is present. Each room, section, or area shall be considered individually in determining its classification. Where pyrophoric materials are the only materials used or handled, these locations are outside the scope of this article. Informational Note No. 1: Through the exercise of ingenuity in the layout of electrical installations for hazardous (classified) locations, it is frequently possible to locate much of the equipment in a reduced level of classification or in an unclassified location and, thus, to reduce the amount of special equipment required.

Refrigerant machinery rooms containing ammonia refrigeration systems that are equipped with adequate mechanical ventilation that operates continuously or is initiated by a detection system that alarms at 1000 ppm at a concentration not exceeding 150 ppm shall be permitted to be classified as “unclassified” locations.

Rooms and refrigerated areas containing ammonia refrigeration systems that are equipped with adequate mechanical ventilation that operates continuously or is initiated by a detection system that alarms at 1000 ppm may be classified as “unclassified” locations.

Informational Note No. 2: For further information regarding classication and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/ ASHRAE 15-2013, Safety Standard for Refrigeration Systems and ANSI/ IIAR 2-2014, Standard for Safe Design of Closed-Circuit Ammonia Refrigeration Systems.

Discussion: IIAR was successful in advocating two changes to the NEC that appear in the 2017 edition. These changes eliminated the longstanding requirement for refrigerated process and storage areas to either be provided with an emergency ventilation system or contain only electrical equipment that complies with Class I, Division 2 or Class I, Zone 2 hazardous (classified) location requirements. The text of Section 500.5 above relates to the NEC’s Class/ Division scheme for protection of hazardous electrical locations. A similar revision, not shown, was made in Section 505.5 for the Class/Zone scheme, which is an optional compliance path commonly used outside of the U.S.

The requirement to provide ventilation or classified electrical equipment in ammonia machinery rooms is widely accepted; however, it has never been industry practice to use this approach for refrigerated process, storage or other areas. Nevertheless, literal application of the previous NEC text, which has now been stricken, put designers and owners at risk of a “gotcha” if a local code official enforced the literal text. The revised provisions in the 2017 edition eliminate the offending text, and instead fall back to the general assessment that is applicable to determining the electrical classification where any flammable liquids or gases are present. In addition, the reference to IIAR 2 and ASHRAE 15 directs code users to the specific guidance in these documents for determining electrical classification and ventilation requirements.

It should be noted that ASHRAE 15 was retained as a reference standard in this edition of the NEC because, at the time this revision was approved, ASHRAE 15 was still scoped to include ammonia refrigeration.

FM DATA SHEETS 7-13,

12-61, AND 12-61R

Discussion: IIAR members who are insured by Factory Mutual (FM Global), have long dealt with supplemental recommendations documented in Historically, FM Global staff members have not sought outside input when developing or updating their provisions, but in the most recent update, they made a unique exception and invited input from IIAR. As a result, the revised FM Global provisions are more closely aligned to industry standards than preceding data sheets.

The updated approach was to merge appropriate provisions from all three data sheets into a single document, a revised DS 7-13 (2018). In addition, provisions were updated Data Sheets 12-61 and 12-61R, which had separately dealt with mechanical integrity, were retired.

Changes to FM recommendations vs. prior provisions are too numerous to cover here, but IIAR members with FM Global insurance can download a free copy of the updated DS 7-13 here: https:// www.fmglobal.com/research-andresources/fm-global-data-sheets.

Part 2 of this article, which includes a review of major changes processing for ASHRAE 15 and the upcoming 2021 model codes, will be published in the next issue.