Mechanical, HVAC & Plumbing Labeling
ASME A13.1 pipe markers, numbered valve tags with matching charts, equipment nameplates, air balance tags, and backflow identification.
ASME A13.1
Pipe marking is a colour code, not a colour choice.
ASME A13.1 assigns a specific legend and field colour combination to each class of pipe contents. Getting it approximately right is the same as getting it wrong — the point of the standard is that a stranger can read the pipe correctly in an emergency.
| Pipe contents | Legend / field | Typical services |
|---|---|---|
| Fire quenching fluids | White on Red | Sprinkler mains, standpipes, fire pump discharge, foam lines. |
| Toxic and corrosive fluids | Black on Orange | Chemical feed, acid and caustic lines, laboratory waste. |
| Flammable fluids | Black on Yellow | Natural gas, propane, fuel oil, solvent lines. |
| Combustible fluids | White on Brown | Diesel, lubricating and hydraulic oil, heat transfer fluid. |
| Potable, cooling, boiler feed and other water | White on Green | Domestic cold and hot water, chilled water, condenser water, boiler feed. |
| Compressed air | White on Blue | Shop air, instrument air, plant compressed air. |
Six standard combinations are shown. ASME A13.1 also defines four user-defined combinations for contents that fall outside these classes. Colours shown are approximations for reference — production uses standard-conforming stock.
Sizing
The pipe diameter decides the letter height.
This is the part that gets missed most often. A correct legend printed too small on a 10-inch chilled water main does not satisfy the standard, and a marker that is right for a ¾-inch line is not right for a 6-inch one.
Note that the governing dimension is the outside diameter including any insulation or covering — not the nominal pipe size. Insulated lines routinely move up a bracket.
Give us your piping schedule or a marked-up plan and we will work out the bracket, quantity, and flow directions for each run. Marker placement guidance ships with the order.
| Pipe OD incl. covering | Colour field length | Letter height |
|---|---|---|
| ¾″ – 1¼″ | 8″ | ½″ |
| 1½″ – 2″ | 8″ | ¾″ |
| 2½″ – 6″ | 12″ | 1¼″ |
| 8″ – 10″ | 24″ | 2½″ |
| Over 10″ | 32″ | 3½″ |
Products
What we make for mechanical work.
ASME A13.1 pipe markers
Correct colour combination for the contents, correct letter height for the outside diameter including insulation, and flow arrows in both directions where the flow can reverse.
Valve tags & valve charts
Numbered brass, aluminum, stainless, or two-ply tags with the matching wall chart or binder schedule. Sequenced so tag 47 in the field is line 47 on the chart.
Equipment nameplates & unit ID
Air handlers, pumps, chillers, boilers, VAV boxes, and rooftop units. Engraved plates that match your equipment schedule and survive a mechanical room.
Air balance & TAB tags
Test and balance identification for diffusers, dampers, and terminal units, formatted to your balancing report.
Backflow preventer tags
Assembly identification, size, model, serial, and test-date fields on stainless or anodized aluminum, built for outdoor enclosures and vault conditions.
Medical gas identification
Piping identification and zone valve labeling for medical gas systems, formatted to NFPA 99 requirements and the facility’s naming conventions.
Boiler & pressure vessel plates
Data plates and identification for boilers, tanks, and pressure vessels where the jurisdiction requires permanent marking.
Mechanical room legends
Framed valve charts, riser diagrams, and equipment legends that put the whole system on one wall instead of in a lost binder.
Valve tagging
A tag is only useful if the chart agrees with it.
Half of the valve tagging we are asked to replace failed for the same reason: the tags were made, hung, and then the chart was written from memory six weeks later. Numbers drifted, valves got re-sequenced, and the chart became fiction.
We produce both from the same source list. You approve one document, and the tags and the chart are generated from it together. Add a valve later and we reissue both.
- Numbered tags in brass, aluminum, stainless, or colour-through two-ply
- Matching wall chart, laminated or framed, plus a PDF for the O&M manual
- Beaded chain, S-hooks, or nylon ties supplied with the order
- Sequence archived, so future additions continue the series correctly
Send us the spec. We’ll send back a quote.
Panel schedule, arc flash study, valve list, a photo of the equipment nameplate — whatever you have. We’ll tell you what the code requires, recommend a substrate, and price it.