Skip to Main Content Accessibility Statement
Bulk Order Pad
Enter full and exact Brady part #'s below:
Ex: M210, 99048, SDPL-RED-38ST-KD6
neutral icon This product is in your cart. We'll update the quantity.
Correct or remove part #s that can't be found.



Floor Tape

Lockout Tagout



Pipe & Valve





Ammonia pipe labeling requirements – IIAR & ASME/ANSI

Pressurized anhydrous ammonia is used as a commercial refrigerant due to its ability to absorb substantial amounts of heat from its surroundings. Industrial settings that use it, including food and beverage processing, cold storage and meatpacking, must adhere to ammonia pipe labeling requirements. Below, we'll break down the standards and requirements, including the ammonia piping color code, lettering and placement set forth by ANSI/ASME, in addition to the International Institute of Ammonia Refrigeration's IIAR Bulletin 114. Before you dig in to the standards, however, it’s important to understand the dangers of ammonia and the importance of using pipe labels and tags on this potentially hazardous chemical.

Dangers of pressurized anhydrous ammonia

Uncontrolled releases of anhydrous ammonia can be harmful to human health, corrosive and explosive when not properly maintained or controlled. Anhydrous ammonia carries a health hazard designation of 3 on the NFPA fire diamond, with threats including:

  • Irritation and corrosiveness to the skin, eyes, respiratory tract and mucous membranes
  • Severe chemical burns and frostbite to the eyes, lungs and skin
  • Aggravation of existing skin and respiratory-related diseases

The EPA has documented a number of accidents, including a meat-packing plant where a refrigeration line ruptured. Eight workers were critically injured, suffering respiratory burns from ammonia inhalation.[1]

Anhydrous Ammonia NFPA sign 

The importance of ammonia pipe labeling

When workers and emergency response personnel follow ammonia pipe labeling standards, it helps effectively identify the pipe and follow where it’s going, especially to valve shutoffs in order to stem further release. Pipes that adhere to IIAR pipe marking standards can also be used in safety training for current and new employees and assist with efficiency during maintenance and servicing. During such events using proper lockout tagout devices, like valve lockouts, in conjunction with proper labels can ensure the safety of you and your team.

Ammonia pipe marking regulations

Two organizations supply documents that inform how ammonia pipes are to be labeled:

ASME (ANSI) A13.1 - 2020: Scheme for the Identification of Piping Systems[2]

This ASME standard is a widely used guideline in determining pipe identification requirements. It indicates that “A13.1 is intended to establish a common system to assist in identification of hazardous materials conveyed in piping systems and their hazards when released in the environment.” Find additional information on ANSI pipe marking standard guidelines.

Pipe Marking Color Codes

Label Color Text Color Pipe Contents
Red White Fire-quenching fluids
Orange Black Toxic and corrosive fluids
Yellow Black Flammable fluids
Brown White Combustible fluids
Green White Potable, cooling, boiler feed and other water
Blue White Compressed air
Purple White Defined by user
White Black Defined by user

IIAR Guidelines for Identification of Ammonia Refrigeration Piping and System Components, Bulletin No. 114, March 2014[3]

IIAR Bulletin 114 is meant to “establish uniform guidelines for identifying piping in a closed-circuit ammonia refrigeration system and the related refrigeration system components.” IIAR Bulletin 114 offers these guidelines specifically for the ammonia refrigeration industry, and uses ASME Standard A13.1 to inform it. As anhydrous ammonia is classified as a “toxic and corrosive fluid,” safety orange is the appropriate base label color.

Important note: IIAR Bulletin 114 was updated in 2014 to accurately reflect safety orange as the primary recommended label color under an update to the ASME standard in 2007. Prior to that, yellow was used. However, this doesn’t mean that all markers, including those made prior to 2014, must be updated. Section 1 of ASME A13.1 states that “Existing schemes for identification shall be considered as meeting the requirements of this Standard if: (a) such schemes are described in writing; (b) employees are trained as to the operation and hazards of the piping system.”

Ammonia pipe marking guide: color code, lettering and positioning


There are 5 sections on an ammonia pipe label that follow the ammonia piping color code and other requirements.

  1. Marker body (ammonia)

    The pipe marker body should be safety orange with “AMMONIA” printed in black letters.

  2. Physical state (liquid, vapor or both)

    Ammonia refrigerant exists in a liquid or vapor state, or both. Following are guidelines for each:

    • Liquid: Print “LIQ” in black letters on a yellow band in a circumferential arc adjacent and left of “AMMONIA”
    • Vapor: Print “VAP” in black letters on a sky blue band in a circumferential arc adjacent and left of “AMMONIA”
    • Liquid and vapor: See first two bullets for color and text guidelines; apply “VAP” adjacent and left of “AMMONIA” and “LIQ” adjacent and left of “VAP”
  3. Pressure (high or low)

    • Pressure greater than 70 PSIG: Print “HIGH” in black letters on a red band in a circumferential arc adjacent and right of “AMMONIA”
    • Pressure less than or equal to 70 PSIG: Print “LOW” in black letters on a green band in a circumferential arc adjacent and right of “AMMONIA”
  4. Abbreviations (HTRL, LTRS, etc.)

    Industrial ammonia refrigeration systems are composed of interconnected pipes with varying temperature, vents, suctions, discharges and more. Abbreviated names identify these specific parts of the system. Abbreviations should be printed in black letters on the safety orange field adjacent and left of the physical state.

  5. Directional arrow ( ← → )

    Directional arrows should be black in color and proportionate in size to the marker. They may or may not be applied around the full pipe circumference.

  6. List of common abbreviations (see sec. 4)

    Abbr. System
    BD Booster Discharge
    CD Condenser
    DC Defrost Condensate
    EQ* Equalizer
    ES Economizer Suction
    HGD Hot Gas Defrost
    HPL High Pressure Liquid
    HSD High Stage Discharge
    HSS High Stage Suction
    HTS* High Temperature Suction
    HTRL High Temperature Recirculated Liquid
    HTRS High Temperature Recirculated Suction
    LTRL Low Temperature Recirculated Liquid
    LTS* Low Temperature Suction
    LTRS Low Temperature Recirculated Suction
    LIC Liquid Injection Cooling
    LSS Low Stage Suction
    PO* Pump Out
    PU* Purge
    RV Relief Vent
    TSR Thermosyphon Return
    TSS Thermosyphon Supply

    *Not currently covered in the IIAR standard

3 easy ways to help you follow ammonia pipe labeling requirements

Put the power of on-demand printing in your facility’s toolbox. Or, select from a variety of preprinted ammonia pipe markers.

Ammonia IIAR pipe market label kit with components, including labels, ribbon and roll

Ammonia (IIAR) Pipe Marker Label Kits

Control messaging and inventory with these modular kits. Simply add specific text and arrow legends to the pipe marker body using Brady Workstation premade templates. Then print using a compatible Brady printer and apply physical state and pressure labels.

BradyJet J4000 industrial label printer sitting on top of a metal shelf

BradyJet J4000 Color Label Printer with Software

Convenience and customization come together perfectly thanks to this this all-in-one inkjet printing solution. Using Brady Workstation software and premade templates, you can easily create full-color labels, hit print once and apply where you need.

Preprinted Pipe Markers

Pre-Printed Ammonia Pipe Markers

Select from markers with prepopulated text. Then choose different sizes and materials that ensure your markers fit where you need and hold up in the environments they face.


  1. Hazards of Ammonia Releases at Ammonia Refrigeration Facilities (Update). U.S. Environmental Protection Agency. (2001, August). Retrieved October 25, 2021, from
  2. A13.1 - Scheme for the Identification of Piping Systems. ASME. (n.d.). Retrieved October 22, 2021, from
  3. Guidelines for: Identification of Ammonia Refrigeration Piping and System Components. International Institute of Ammonia Refrigeration (IIAR). (2014, March). Retrieved October 22, 2021, from

Product Recommendations


Various hazardous materials, all properly labeled according to NFPA 704 standards.

NFPA 704 Labeling Guide

Understand this history, elements and implementation of the NFPA 704 Hazard Diamond.

Learn More
A guide to ANSI Pipemarking Standards.

ANSI Pipemarking Standards

What are OSHA's requirements related to ANSI Pipe Marking Standards?

Learn More

Safety Signs and Symbols Standards

Understand the types, requirements and use for workplace safety signs and symbols.

Learn More

{{itemAddedCount}} item added to cart.

{{itemAddedCount}} items added to cart.

Cart Subtotal ({{totalItemCount}}): {{subtotal}}
View Cart
Products Added
{{item.CustomerSpecificDisplayName || item.DisplayName}}
{{item.CustomerSpecificDisplayName || item.DisplayName}}
Part Number: {{item.CatalogNumber}}
Your Part Number: {{item.CustomerSpecificCatalogNumber}}

Thou shalt ship ship by ground only

QTY: {{item.ProductQuantity}}
QTY: {{item.Quantity}}
Price: {{item.FormattedProductPrice}}

Sorry, there was a problem adding your item. Please try again.