Ammonia Pipe Marking Guide: IIAR Bulletin #114
How ammonia refrigeration piping and components are identified under IIAR Bulletin #114: what each part of the marker means, the system abbreviations, marker sizes and where markers go.
What Bulletin #114 is
IIAR Bulletin #114, Guideline for Identification of Ammonia Refrigeration Piping and System Components, was developed and published in 1991 by the International Institute of Ammonia Refrigeration to establish uniformity among ammonia refrigeration users in identifying refrigerant piping.
The guideline was based on ANSI Standard A13.1-1981, Scheme for Identification of Piping Systems. That standard was further revised in 2020 and included a change from a yellow background to an orange background for toxic and corrosive fluids. Bulletin #114 updates the IIAR standard to reflect the ASME changes and provide better consistency with general industry standards.
- The use of color to identify fluid characteristics is suggested and adopted by the bulletin in an effort to bring consistency to the industry and aid in training and safety efforts.
- The suggested color scheme is not intended to replace existing color schemes that have been established by facilities.
Scope
The bulletin establishes guidelines for identifying piping in a closed-circuit ammonia refrigeration system, as well as related refrigeration system components.
- All piping mains, headers and branches should be identified as to the physical state of the refrigerant (vapor, liquid, etc.), the relative pressure level and the direction of flow.
- All refrigerant system components should also be uniformly identified: compressors and compressor units, condensers, receivers, thermosyphon vessels, recirculators, intercoolers, accumulators, transfer vessels, oil pots, evaporators, heat exchangers and any other component of the system containing refrigerant.
Reading an ammonia pipe marker
A marker identifies the refrigerant in that piping segment, including its physical state, relative pressure level and direction of flow. Each marker has five sections.
- APiping abbreviation. The IIAR system abbreviation, in black letters on an orange background.
- BPhysical state. LIQ in black letters on a yellow band and/or VAP in black letters on a baby blue band.
- CAmmonia. The word AMMONIA in black letters on an orange background.
- DPressure level. Under 70 psig is low pressure: the word LOW in black letters on a green band. Over 70 psig is high pressure: the word HIGH in black letters on a red band.
- EDirection of flow. A black arrow on the orange background, scored for use in either direction. On vinyl snap-on markers the arrows and legend are printed universally, so the arrows point the right way however the marker is positioned.
System abbreviations
The IIAR abbreviations, with the physical state and pressure level printed on the stock marker for each.
| IIAR abbrev. | System | Physical state | Pressure level |
|---|---|---|---|
| BD | Booster Discharge | VAP | LOW |
| BS | Booster Suction | VAP | LOW |
| CD | Condenser Drain | LIQ | HIGH |
| DC | Defrost Condensate | LIQ | HIGH |
| ES | Economizer Suction | VAP | LOW |
| EQ | Equalizer | VAP | HIGH |
| FG | Foul Gas | VAP | LOW |
| HPL | High Pressure Liquid | LIQ | HIGH |
| HSD | High Stage Discharge | VAP | HIGH |
| HSS | High Stage Suction | VAP | LOW |
| HTRL | High Temperature Recirculated Liquid | LIQ | LOW |
| HTRS | High Temperature Recirculated Suction | LIQVAP | LOW |
| HTS | High Temperature Suction | VAP | LOW |
| HG | Hot Gas | VAP | HIGH |
| HGD | Hot Gas Defrost | VAP | HIGH |
| IPL | Intermediate Pressure Liquid | LIQ | HIGH |
| LD | Liquid Drain | LIQ | LOW |
| LIC | Liquid Injection Cooling | LIQ | HIGH |
| LT | Liquid Transfer | LIQ | LOW |
| LSS | Low Stage Suction | VAP | LOW |
| LTRL | Low Temperature Recirculated Liquid | LIQ | LOW |
| LTRS | Low Temperature Recirculated Suction | LIQVAP | LOW |
| LTS | Low Temperature Suction | VAP | LOW |
| MTRL | Medium Temperature Recirculated Liquid | LIQ | LOW |
| MTRS | Medium Temperature Recirculated Suction | LIQVAP | LOW |
| MTS | Medium Temperature Suction | VAP | LOW |
| OD | Oil Drain | — | — |
| PO | Pump Out | LIQ | LOW |
| PU | Purge | LIQ | HIGH |
| PL | Purge Line | VAP | HIGH |
| RV | Relief Vent | — | — |
| RV | Relief Vent | VAP | HIGH |
| TSR | Thermosyphon Return | LIQVAP | HIGH |
| TSS | Thermosyphon Supply | LIQ | HIGH |
| TSV | Thermosyphon Vent | VAP | HIGH |
Relief Vent (RV) is stocked two ways: with VAP / HIGH bands, and with no state or pressure bands.
Marker dimensions and lettering size
IIAR Bulletin #114, Section 4.1.8. Pick the marker by the outside diameter of the pipe, including insulation.
| Pipe diameter (O.D.) | Marker width | Marker length | Letter size | Physical state | Pressure level | ColdMark™ style |
|---|---|---|---|---|---|---|
| Up to 1.25" | 1" | 8" | .5" | .5" | .5" | AR1 |
| Over 1.25" to 2" | 1.5" | 8" | .75" | .75" | .75" | AR2 |
| Over 2" to 7" | 2.5" | 12" | 1.25" | 1" | 1" | AR3 |
| Over 7" to 10" | 3.5" | 24" | 2.5" | 1.5" | 1.5" | AR4 |
| Over 10" | 4.5" | 32" | 3.5" | 2" | 2" | AR5 |
Marker material requirements
- Pipe markers may be of the self-adhesive, snap-on or strap-on type. Choose the type of marker system that best suits the area of use.
- Prepare the pipe surface. Thoroughly degrease, clean and dry the pipe before installing a self-stick marker, to avoid trapping moisture, which can cause corrosion on uninsulated piping systems.
- Markers should resist fading from indoor and outdoor ultraviolet (UV) or infrared radiation.
- Markers must be suitable for application to insulated or non-insulated piping.
- Self-stick markers must have an adhesive backing that adheres in all temperature ranges served by the refrigeration system and retains its adhesive qualities when applied to outdoor piping.
Component markers
Component markers bear the name of the equipment they identify, such as RECEIVER, ACCUMULATOR or RECIRCULATOR, along with a pressure level designation.
3.5" wide and up to 32" long, with 2.5" tall lettering.
- Black letters on an orange background.
- Pressure level is shown by the word HIGH in red letters (over 70 psig) or LOW in green letters (70 psig or less) on the far right-hand side of the marker.
- Component markers are 3.5" wide by up to 32" long, to accommodate the name of the component.
- Lettering is 2.5" tall.
- Self-stick markers follow the same material guidelines as the ammonia pipe markers.
Where to place markers
Simplified location and usage guidelines.
Shop ammonia identification
This page summarizes IIAR Bulletin #114 for reference. Consult the current bulletin from the International Institute of Ammonia Refrigeration for the complete guideline.
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