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Ammonia Refrigeration Valve Tagging

Writer's picture: MySafety LLCMySafety LLC

Updated: 7 days ago

Which regulatory agency requires ammonia refrigeration valves to be identified (valve tagged)? The answer isn't as clear-cut as you would think.


Let's start with the following for reference:

  • Occupational Safety and Health Administration (OSHA) Control of Hazardous Energy 1910.147(c)(7)(i) (Lockout/Tagout) states "The employer shall provide training to ensure that the purpose and function of the energy control program are understood by employees and that the knowledge and skills required to the safe application, usage, and removal of the energy controls are acquired by employees".


The regulation above doesn't say word for word that valve tags need to be installed. But the implementation of valve tags would significantly improve the application and usage to employees. Unless you have some other method besides using valve tags for identification.


Furthermore, ammonia refrigeration systems with 10,000 lbs. or more are regulated by OSHA's Process Safety Management (PSM) standard. The PSM standard doesn't have any required regulation for the installation of valve tags either, but the PSM standard does require Block Flow Diagrams, Standard Operating Procedures (SOPs), & Piping & Instrumentation Diagrams (P&IDs) for the process.

Reference:

  • OSHA's PSM 1910.119(d)(2)(i)(A) A block flow diagram or simplified process flow diagram.

  • OSHA's PSM 1910.119(d)(3)(i)(B) Piping and instrument diagrams (P&ID's).

  • OSHA's PSM 1910.119(f)(1) The employer shall develop and implement written operating procedures that provide clear instructions for safely conducting activities involved in each covered process consistent with the process safety information and shall address at least the following elements.


If someone is handed an SOP and P&ID without identified valves and they're asked to safely carry out assigned tasks, that would be challenging for personnel. OSHA's PSM does have a regulation that is similar to the information found in 1910.147(c)(7)(i) (Control of Hazardous Energy).


Reference:

  • OSHA's PSM 1910.119(f)(4) "The employer shall develop and implement safe work practices to provide for the control of hazards during operations such as lockout/tagout; confined space entry; opening process equipment or piping; and control over entrance into a facility by maintenance, contractor, laboratory, or other support personnel. These safe work practices shall apply to employees and contractor employees."


But technically speaking, the PSM standard doesn't require the installation of valve tags word for word. So, let's dig a little deeper into the Pandora's Box of standards/regulations. If your facility has adopted the International Institue of All-Natural Refrigeration (IIAR) as your Recognized and Generally Accepted Good Engineering Practices (RAGAGEP), then you're adopting IIAR's minimum requirements. This includes the following IIAR requirements for Signage, Labels and Pipe Marking in:


  • ANSI/IIAR 2-2021 (Standard for Design of Safe Closed-Circuit Refrigeration Systems) in Section 5.14.4

  • ANSI/IIAR 9-2021 (Standard for Minimum System Safety Requirements for Existing Closed-Circuit Ammonia Refrigeration Systems) in Section 7.2.9.3.


IIAR 2 (5.14.4) & IIAR 9 (7.2.9.3) are both for Emergency Shut-off Valve Identification and Tagging Valves required for emergency shutdown of the system shall be clearly and uniquely identified at the valve itself and in the system schematic drawings.


This is where the requirement comes from to have valve tags or some similar method to uniquely identify valves on the ammonia system. To know which valves to identify, reference the equipment emergency shutdown section of the SOP. Equipment examples include auto-purger, RMAU, compressors, condensers, evaporators, heat exchangers, oil pots, accumulators, recirculators, pressure vessels, etc. Valves that would be identified can include main isolation valves, service valves, control valves (flow & pressure), etc. It all depends on your site-specific emergency shutdown procedures for the equipment.


At this point, when a SOP & P&ID need to be conducive for employees, valve tag identification helps accomplish this. Not every designer will identify valves the same way either. For example, at one facility the ammonia strainers are not identified on the P&ID, but the next facility you go to does identify ammonia strainers on the P&ID. It all depends on the designer's preference. Another example is when a screw compressor package doesn't have every single valve on the oil circuits tagged. This doesn't mean the facility is not in compliance. To better communicate the steps to control hazardous energy to employees, the designer can use their discretion and decide to identify oil circuit valves on a compressor or any other valves throughout the ammonia system.


The next question that is brought up frequently about valve tags is what information needs to be displayed on the valve tag. IIAR does not provide a standard for the tagging of valves with regards to the unique number or the information that is to be displayed on the tag. In the early days of PSM it was typical for a valve tag to display just the unique number that was assigned to that valve, such as 252 or 535. To obtain additional information or specifications of the valve, personnel would then refer to the Master Valve List which contained the related information and specifications for the valve. However, over time the valve number itself has evolved into a “valve name” and an abundance of related information is also being added to the tag number or tag itself. For example, a valve number may be HV-01, ST-02 or PR-03, which describes Hand Valve 01, Strainer 02 and Pressure Regulator Valve 03 respectively. The tag will also contain the equipment identification such as EV-01, the room that the valve is in such as room F, as well as the line designation for that valve such as HTRL. Now the tag would read as EV-01 / F / PR-03 / HTRL. Some tags add even more information like valve position and valve size and therefore would read as EV-01 / F / PR-03 / HTRL / N-O / 2”. But with a typical valve tag being approximately 3” x 3”, the more information that is put on the tag causes the font to get smaller to contain all the information in the given space. Also, considering that during an emergency response event the responder is looking through the visor of the full-face mask as well as the visor of the fully encapsulated suit, it becomes difficult to quickly identify the valve with the font being small and being blended with so much additional information. Rather than just a 3” x 3” tag with only a valve number displayed, which has a much larger font. How much information is too much information? Leave us a comment below, what’s on your valve tags?


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Ammonia refrigeration valve tagging.
Ammonia Refrigeration Valve Tagging

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