Access to Refrigeration Systems

It has long been required that access be considered when designing and installing an ammonia refrigeration system. In fact, we wrote about this topic in some detail back in 2013. Since a decade has passed, it seems appropriate to revisit the relevant access requirements contained within the current RAGAGEP documents applicable to ammonia refrigeration.

ANSI/IIAR 9-2020

For existing ammonia refrigeration systems, the applicable RAGAGEP is ANSI/IIAR 9-2020 “Standard for Minimum System Safety Requirements for Existing Closed-Circuit Ammonia Refrigeration Systems”. The standard addresses two categories of accessibility: General Accessibility, and Access to Valves. 

General Accessibility

Regarding general accessibility, ANSI/IIAR 9-2020 §7.2.8 requires that “Equipment shall be accessible for inspection testing, maintenance, and emergency shutdown.” Additionally, service egress must be provided:

• 7.2.11.2 Egress. Operational and maintenance service egress shall be provided by access panels or doors, or shall provide for remote service by removal of the enclosure or the contents from the installed location.

Access to Valves

Safe access to manually operated valves must be provided. ANSI/IIAR 9-2020 §7.3.3.3 lists the following requirements for manually operated valves that are inaccessible from floor level, and manually operated isolation valves identified as being part of the system emergency shutdown procedure.

• 7.3.3.3 Access to Valves. 

1. Manually operated valves that are inaccessible from floor level shall be operable from portable platforms, fixed platforms, ladders, or shall be chain operated
2. Manually operated isolation valves identified as being part of the system emergency shutdown procedure shall be directly operable from the floor or chain operated from a permanent work surface. Emergency shut-off valve identification shall comply with Section 7.2.9.3

ANSI/IIAR 2-2021

For new ammonia refrigeration systems, the applicable RAGAGEP is ANSI/IIAR 2-2021. This is the Standard for Design of Safe Closed-Circuit Ammonia Refrigeration Systems. This standard addresses four categories of accessibility: Access to Equipment, Service Provision, Access to Valves, and Restricted Access. 

Access to Equipment

ANSI/IIAR 2-2021 §5.12.1 contains the general requirements for accessing equipment:

ANSI/IIAR 2-2021 §5.12.1 General. Equipment shall be accessible for maintenance, as required by the Mechanical Code.

Depending on the model code enforced in your jurisdiction, one of the two codes referenced below would be applicable:

2021 IMC §306.1 Access. Appliances, controls devices, heat exchangers and HVAC system components that utilize energy shall be accessible for inspection, service, repair and replacement without disabling the function of a fire-resistance-rated assembly or removing permanent construction, other appliances, venting systems or any other piping or ducts not connected to the appliance being inspected, serviced, repaired or replaced. A level working space not less than 30 inches deep and 30 inches wide (762 mm by 762 mm) shall be provided in front of the control side to service an appliance.

2024 UMC §304.1 General. All appliances shall be located with respect to building construction and other equipment so as to permit access for repair or replacement of the appliance. Clearance shall be maintained to permit removal of the appliance; cleaning of heating surfaces; the replacement of filters, blowers, motors, burners, controls, and vent connections; the lubrication of moving parts where necessary; the adjustment and cleaning of burners and pilots; and the proper functioning of explosion vents, if provided. For attic installation, the passageway and servicing area adjacent to the appliance shall be in accordance with Section 304.4. {NFPA 54:9.2.1} Unless otherwise specified, not less than 30 inches (762 mm) in depth, width, and height of working space shall be maintained.

Similarly, ANSI/IIAR 2-2021 §6.3.1 requires equipment in machinery rooms to be accessible and prohibits restriction of emergency egress.

ANSI/IIAR 2-2021 §6.3.1 General. Equipment installed in machinery rooms shall be located in such a manner as to allow egress from any part of the room in the event of an emergency, and to provide clearances required for maintenance, operation, and inspection according to manufacturers’ instructions.

Service Provision

Three (3) instances requiring service provision to equipment exist within ANSI/IIAR 2-2021:

ANSI/IIAR 2-2021 §6.3.2 Maintenance Access. Maintenance access shall comply with Section 5.12.1.

ANSI/IIAR 2-2021 §7.2.7 Service Provisions. Service provisions shall comply with Section 5.15.

ANSI/IIAR 2-2021 §12.6.1 Pressure vessel access shall be provided in accordance with Section 5.12.

Access to Valves

In addition to requiring access to equipment, access to valves is required in four (4) instances:

ANSI/IIAR 2-2021 §5.12.5.1 Manually operated valves that are inaccessible from floor level shall be operable from portable platforms, fixed platforms, ladders, or by use of a chain or a remote-actuated manual operator.

ANSI/IIAR 2-2021 §5.12.5.2 Manually operated isolation valves identified as being part of the system emergency shutdown procedure shall be directly operable from the floor or a remote-actuated manual operator that is operated from a permanent work surface. Accessibility and clearance to operate the valves while wearing emergency response personal protective equipment shall be provided. Emergency valve identification shall comply with Section 5.14.4.

ANSI/IIAR 2-2021 §13.3.2.8 Valves required for system emergency shutdown procedures shall be readily accessible and identified in accordance with Sections 5.12.5.2, 5.14.1 and 5.14.4. Other valves shall be accessible in accordance with Section 5.12.5.1.

ANSI/IIAR 2-2021 §15.2.4 Relief device arrangements shall be configured such that it is possible to safely access them for inspection, maintenance, and repair.

Restricted Access

While the paragraphs thus far clearly outline the requirements for accessibility, ANSI/IIAR 2-2021 also requires access to be restricted to certain areas:

ANSI/IIAR 2-2021 §6.3.3 Restricted Access. Access to a machinery room shall be restricted to authorized personnel. Signage on machinery room doors shall comply with Section 6.15.

ANSI/IIAR 2-2021 §6.15.3 Restricted Access Signage. Each machinery room entrance door shall be marked with a permanent sign to indicate that only authorized personnel are permitted to enter the room.

ANSI/IIAR 2-2021 §7.2.2 Access [non-machinery room spaces]. Access to the refrigeration equipment shall be restricted to authorized personnel.

ANSI/IIAR 2-2021 §16.1.5 Restricted Access to Safety Settings. Changing of safety settings shall be limited to authorized personnel only. Changing of system operational settings shall not permit or affect changes to safety settings.

Summary

Care must be taken to ensure that equipment and valves are safely accessible for inspection and maintenance. Additionally, access restrictions must be in place to prevent unauthorized persons from making setpoint changes or working in areas that are not intended for normal occupancy.