Blank Plastic Valve Tags: Sizes, Hole Sizes and When to Order Blank vs Pre-Engraved
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You are tagging a mechanical room and the blank tags are cheaper and in stock, but the spec says the markings have to last. Do blanks work, or do they just move the work to someone with a marker?
Disclaimer: general information, not legal or compliance advice. Codes change and inspectors interpret them differently, so confirm requirements with a qualified professional. Full disclaimer
What a blank valve tag is, and what it is not
A blank plastic valve tag is a round tag with a punched hole and nothing on it. It is usually made from two-ply plastic, with a contrasting core and face so that text, once added, reads clearly. Blanks come in a few standard diameters and a range of colors.
What a blank does not have is any identification. Somebody still has to put a valve number and a service on it. That single fact decides most of the blank versus pre-engraved question, and the rest of this article works from it.
Common diameters and hole sizes
Most HVAC and mechanical work uses three diameters: 1.5 inch, 2 inch and 2.5 inch. The hole is commonly around 1/4 inch, with 3/16 inch also seen on smaller tags. Hole size varies by supplier, so confirm it before you buy chain or wire to go with it.
- 1.5 inch valve tag: the smallest size most contractors order. It fits tight spaces and small handles, but the text area is limited.
- 2 inch valve tag: the usual all-around choice for mechanical rooms. It holds a short tag number and a service abbreviation at a size you can read from a few feet away.
- 2.5 inch valve tag: for larger valves, higher ceilings, or any place where the reader will be standing back from the valve.
For a closer look at how much text each diameter holds, see the valve tag size chart.
Which tag fits which valve
Ball valve handles
Lever handles on ball valves usually have a small hole or a slot near the end. A 1.5 inch or 2 inch tag on a short chain or a cable tie works well here. Keep the tag clear of the lever travel so it does not catch on piping or insulation when the valve is operated.
Gate valve handwheels
A handwheel has open spokes, so a tag can be tied directly to a spoke or hung from the stem nut. A 2 inch or 2.5 inch tag is typical. Wire or cable ties hold better than a loose chain when the wheel is turned often, because a long chain can wrap around the stem.
Small-bore needle valves
Needle valves on gauges, drains and instrument lines have small handles and little clearance. A 1.5 inch tag is usually the right size. Use a short length of wire or a small cable tie, and check that the tag does not rest against hot piping.
Tag size, characters per line and attachment
The figures below are approximate. Characters per line depends on letter height, font and whether you use one, two or three lines.
| Tag diameter | Approx. characters per line | Best use | Typical attachment |
|---|---|---|---|
| 1.5 in | About 6 to 8, two or three lines | Small ball valves, needle valves, gauge isolation | Small cable tie or short wire loop |
| 2 in | About 8 to 10, two or three lines | General mechanical room valves, ball valves, handwheels | Chain, wire or cable tie |
| 2.5 in | About 10 to 12, three lines | Large valves, long sight lines, tag number plus service plus direction | Chain or heavy wire; cable tie on spoked handwheels |
The valve tag attachment guide covers chain, wire and tie options in more detail. The short version: match the attachment to the handle opening, not the other way around. A chain with links too large for the hole will bind, and a cable tie that is too thick will not pass through at all.
The practical limit of blanks
A blank tag is only the substrate. The markings have to be added by hand with a paint pen, marker or label, and none of those are permanent in a mechanical room. Heat, condensation, cleaning chemicals and handling all wear them down. Handwritten or marker text fades, and it can smear or rub off long before the building is turned over.
That matters because many project specifications call for identification that stays legible for the life of the system. Specifications written around MasterFormat Section 23 05 53, for example, commonly describe identification of piping, valves and equipment in terms of legible, durable markings. Read the actual wording in your project spec, because it varies by project and edition, and your engineer or AHJ makes the call on what is acceptable. A blank tag with hand-applied text is hard to defend against a spec like that. Engraved text is part of the tag itself, so it does not rub off the way printed or written ink can.
For more on how those specs are usually written, see Section 23 05 53 and engraved tags.
When blanks still make sense
Blanks are not useless. They have a place when the marking is temporary or the identity is not known yet.
- Spares in the service truck for a valve that gets added during a repair.
- Commissioning and startup tagging where tags are written on and removed.
- Out-of-service or lockout tagging under your own site procedure.
- Valves that are not yet scheduled and will be identified once the drawings are final.
If the tag is going to stay on the valve and the spec asks for permanent identification, order it pre-engraved.
Worked example: a 40-valve mechanical room
Say a mechanical room has 40 valves on chilled water, heating hot water and condenser water. The spec calls for permanent identification on every scheduled valve. Here is one way to split the order.
- 28 pre-engraved 2 inch tags for the scheduled valves, each with a tag number and a service.
- 12 blank 2 inch tags in the same color scheme, held as spares for future valves and temporary use.
A sample line list for the engraved tags might look like this:
- CHW-01 / CHILLED WATER SUPPLY
- CHW-02 / CHILLED WATER RETURN
- HHW-01 / HEATING HOT WATER SUPPLY
- HHW-02 / HEATING HOT WATER RETURN
- CW-01 / CONDENSER WATER SUPPLY
- CW-02 / CONDENSER WATER RETURN
Check the text against the character count before you order. A line such as CHILLED WATER SUPPLY will need abbreviation or a smaller font on a 2 inch tag, so a 2.5 inch tag or a shortened service (CHWS) may be the better choice. Settle on the abbreviations with the engineer first so the tags match the schedule and the drawings.
Ordering cautions
- Confirm the color scheme before ordering. Colors by service are set by the project spec or the owner's standard. Reordering a color after the room is tagged is expensive and slow.
- Order about 10 percent spare on engraved tags. Valves get added, tags get lost during maintenance, and a short run is harder to match later.
- Match the attachment to the handle opening. Measure the hole in the handle or the spoke gap, then choose chain, wire or cable tie to suit.
- Check for heat. Plastic tags near very hot piping can deform. If the line runs hot, ask about stainless instead.
Frequently Asked Questions
What size is a standard valve tag?
There is no single standard, but 1.5 inch, 2 inch and 2.5 inch diameters are the most common. A 2 inch tag is the usual default for mechanical rooms because it balances readability and fit.
What size hole do blank valve tags have?
Commonly around 1/4 inch, with 3/16 inch also available. Hole size depends on the supplier, so confirm it before you choose a chain, wire or cable tie.
Can I write on blank plastic valve tags with a marker?
You can, but the text is not permanent. Marker and paint pen fade with heat, moisture and handling, so it is better suited to temporary use than to a spec that calls for durable identification.
How many characters fit on a 1.5 inch valve tag?
Roughly 6 to 8 characters per line on two or three lines, depending on letter height. If you need a longer service description, step up to a 2 inch or 2.5 inch tag.
How many spare tags should I order?
About 10 percent over the count is a common allowance. Adjust it up if you expect valves to be added after turnover.
Choose blank or pre-engraved valve tags in the sizes and colors your spec calls for.
If the same job also needs line identification, look at our pipe markers, and for equipment and panel plates, the rectangle lamacoid configurator lets you set size, color and text. The valve tag catalog has blanks and pre-engraved tags in the common diameters.
Disclaimer. This article is provided for general informational purposes only and does not constitute legal, safety, or professional compliance advice. Regulations, standards, and codes are subject to change and may be interpreted differently by authorities having jurisdiction (AHJ). Always consult with qualified safety professionals, licensed engineers, or legal counsel to determine the specific requirements applicable to your facility. TagBuilder is not responsible for any actions taken based on this information.
UL, NFPA, NEC, ASME, CEMA, TIA, ANSI and OSHA are names or marks of their respective organizations; TagBuilder is not affiliated with or endorsed by any of them. Requirements above are paraphrased summaries, not the text of any standard. Always work from the current published edition and your AHJ.
