Getting pipe marking AS 1345 right comes down to three things: the correct identification colour for what's inside the pipe, a clear contents legend, and a flow-direction arrow. Do those three well and anyone walking into a plant room can read your pipework at a glance. This is the plain-English guide to pipe identification labels in Australia — colours, legend, arrows, placement — and where engraved pipe and valve ID plates earn their keep.
AS 1345-1995, "Identification of the contents of pipes, conduits and ducts", is the standard that sets it out. It's still current. It leans on AS 2700 for the actual colour definitions, and where there's a hazard to the operator it cross-refers to AS 1319 for the warning wording.
Pipe marking colours under AS 1345
Every base identification colour maps to a category of contents. Match the colour to what the pipe carries and you're most of the way there. Here are the AS 1345 pipe marking colours by name:
| Identification colour | Contents category |
|---|---|
| Green | Water — potable, cooling, wastewater, storm water, recycled |
| Silver-grey | Steam |
| Brown | Oils, flammable and combustible liquids |
| Sand / yellow-ochre | Gases — fuel and process gases, LPG, medical gases |
| Violet | Acids and alkalis (corrosives) |
| Light blue | Air — compressed, ventilation, instrument air |
| Red | Fire protection — water, sprinkler and hydrant services dedicated to fire |
| Orange | Electrical conduits and cables |
| Black | Miscellaneous — chemical mixtures, sewage, process wastes, other liquids |
| White | Communications |
| Dark blue | Supplementary services |
The colour itself comes from AS 2700 — that's the swatch reference AS 1345 calls up so a green is the same green on every job. On an engraved label you achieve it by choosing a laminate whose top colour matches the category, then cutting the legend through to the contrasting core.
The contents legend — name the contents, don't just colour-code
Colour alone isn't enough. A compliant marker carries the contents legend too — the name of what's inside, or a recognised abbreviation, in white or black text for contrast against the base colour.
Be specific. "POTABLE WATER" tells a worker far more than a bare "WATER", and it's the kind of wording that prevents the wrong valve getting cracked open. Where space is tight on smaller-bore lines, a clear abbreviation plus the flow arrow does the job.
Flow-direction arrows
Add a flow-direction arrow so it's obvious which way the contents move. On a bidirectional line, mark arrows for both directions. The arrow lives alongside the colour band and the legend so the three read together as one marker.
Hazard and potable-water bands
Two extra bands sit on top of the base scheme:
- Human consumption. Pipes carrying contents intended for human consumption — potable water — get an additional dark-blue band at least 75mm wide.
- Special hazard. Where the contents present a special hazard to operators, add a yellow band or patch at least 75mm wide, with the hazard wording set out per AS 1319.
Colour says the category. The legend says the exact contents. The arrow says which way it flows. The extra bands flag "you can drink this" or "this can hurt you". A worker should read all of that in one glance, from a safe distance.
Text height by pipe size
The bigger the pipe and the further away you read it from, the larger the marker and legend need to be. A common rule used across the trade for legend text height runs like this:
| Pipe outside diameter | Minimum text height (commonly specified) |
|---|---|
| Under 25mm | 10mm or more |
| 25–100mm | 20mm or more |
| Over 100mm | 50mm or more |
Treat those figures as a practical sizing guide rather than a clause to quote — the overriding principle is that the marker scales with pipe diameter and viewing distance so it stays legible. Our online label designer lets you set the size and preview the legend before you order, so you can match the text height to the run.
Where to put the markers
Placement is where a lot of jobs fall short. AS 1345 wants markers where people actually interact with the pipework:
- Adjacent to all junctions
- At every valve
- At service appliances
- Either side of bulkheads
- At wall and floor penetrations
- At intervals no greater than 8m along the run — longer spacing only on uninterrupted external straights
Where engraved valve and line ID plates fit
AS 1345 already wants a marker adjacent to every valve. That's exactly where printed wrap markers struggle — plant rooms, pump stations, wet and industrial areas where heat, moisture and handling fade printed film over time.
This is the case for engraved two-colour laminate. The legend is cut into the material, so the contents name, abbreviation and flow arrow can't rub off or peel. Match the laminate's top colour to the AS 1345 category — for example a green-cap laminate with engraved white text for a water line — and you've got a durable, professional valve or line ID plate that reads the same in five years as it does on day one.
Stock colours cover most of the scheme straight off the shelf: green/white for water, red/white for fire services, blue/white for air, yellow/black for gases, plus special-order colours for the rest. Fix them with self-adhesive backing, mounting holes, or wire-through tags to suit the location. For the valve side of the job, see our valve tags and the custom cable tags and valve tags guide.
One honest note on outdoor runs: the engraved legend itself can't fade because it's cut into the material, but the laminate substrate can chalk under years of direct sun. For long-term external or coastal exposure, ask about a UV-stable grade or a metal plate.
Made by a qualified electrician in Townsville and shipped Australia-wide, with 1–3 business day production and no minimum order. Spec your pipe and valve ID plates in the label designer, or call us on 0432 736 559 to talk it through.
References
- AS 1345-1995 — Identification of the contents of pipes, conduits and ducts
- AS 2700 — Colour standards for general purposes (colour definitions called up by AS 1345)
- AS 1319 — Safety signs for the occupational environment (hazard-warning element)
- AS 2419.1 — Fire hydrant installations (complementary fire-services standard)
This article summarises publicly available guidance on pipe identification and is not a substitute for professional advice or the direction of your certifier or inspector. Always confirm the requirements against the current edition of the relevant standard before you fabricate or install.