How to Read Steam Hose Pipe Specifications Before You Send an Enquiry

How to read a steam hose pipe specification before you send an enquiry

A steam hose spec sheet is seven lines long. Read each one for what it actually promises, send the five details a supplier needs, and the quote that comes back will match the duty on your plant.

Flexihose rubber steam hose: one wire braid 145 PSI / 10 BAR working, 1450 PSI / 100 BAR minimum burst, −40 °C to +195 °C, 1/2" to 2" · two wire braid 250 PSI / 17 BAR working, 2500 PSI / 170 BAR minimum burst, −40 °C to +232 °C, 1/2" to 1-1/4" · exceeds IS 10655 Type 2 / Type 3

A steam hose enquiry written as one line, “steam hose pipe, 1 inch, 50 metres, send rate”, can be priced at our Bhiwadi works, but we cannot be sure the hose we quote is the hose your plant needs, because the line leaves out the two numbers that decide the grade. A purchase order raised on a half-read spec sheet is how a 10 BAR hose ends up on a line that runs hotter than its rating. This guide covers the seven lines on a steam hose spec sheet, why working and burst pressure differ, the five details a supplier needs to quote, and the red flags to check before you raise the PO.

Seven lines on a steam hose spec sheet and what each one means

A complete specification for an industrial rubber steam hose fits on a single card. We print the same seven lines for both of our grades, and we would expect any supplier to print them too. Here is what each line tells you, and what it does not.

1. Working pressure, the limit for everyday use

This is the highest pressure the hose is rated to carry in normal service. On our one wire braid grade it is 145 PSI / 10 BAR, and on the two wire braid grade 250 PSI / 17 BAR. Two points matter for a buyer. First, the figure applies to the pressure at the hose, after any reducing station, not to the boiler nameplate. Second, on our steam hose the working pressure is the same at every bore within a grade, so a 2" hose of the one braid grade is rated exactly as a 1/2" hose. That is not true of every hose family. Our PTFE and stainless steel ranges lose pressure rating as the bore rises, so on those you read the figure at your size.

2. Minimum burst pressure, a test figure and not a capacity

Burst is the pressure at which a sample of the hose is expected to fail in a hydrostatic test. We publish a minimum of 1450 PSI / 100 BAR for the one braid grade and 2500 PSI / 170 BAR for the two braid grade. The word “minimum” is important: it is the floor the hose must clear, not a typical value. The next section explains why this number is never a pressure you plan to run at.

3. Service temperature, the second ceiling

Our one braid grade is rated −40 °C to +195 °C and the two braid grade −40 °C to +232 °C. Steam brings temperature with pressure. Spirax Sarco’s steam table gives a saturation temperature of 170 °C at 7 bar g (Spirax Sarco, What is steam), and superheated steam runs hotter than its pressure alone suggests. So a duty can sit inside the pressure line and outside the temperature line. Specify the grade on whichever of the two pushes you higher; our guide to saturated and superheated steam works through that case.

4. Bore, the inside diameter that sets the size

The size you order is the bore: the inside diameter, quoted in inches with a millimetre equivalent. Our sizes run 1/2" (12.50 mm) to 2" (50.00 mm) on the one braid grade and 1/2" to 1-1/4" (31.00 mm) on the two braid grade. When you replace a hose, measure the inside, not the outside. The full chart for every bore is in our guide to steam hose pipe sizes.

5. Mean outside diameter, the figure the coupling must match

Two hoses with the same bore can have different outside diameters, because a second braid adds wall. Our 1" hose measures 35.50 mm mean OD in the one braid grade and 38.00 mm in the two braid grade. Steam couplings are sized to the outside diameter, so a spec sheet that gives bore alone leaves the fitter guessing. If a supplier cannot tell you the mean OD, the coupling has not been thought about.

6. Reinforcement, which tells you how the hose holds its pressure

Our grades carry one or two braids of high-tensile brass-coated steel wire under an EPDM cover, over a heat-resistant EPDM tube. Steel matters because textile yarn loses tension under repeated heat cycling; brass coating matters because it bonds the wire to the rubber. A sheet that says only “reinforced” has not told you which. Our full construction and size tables are on the steam hose page.

7. The standard claim, and the exact verb used

Our one braid grade exceeds IS 10655 Type 2 and the two braid grade exceeds IS 10655 Type 3. Neither holds a BIS licence, and we do not describe either as certified. The verb on this line carries legal weight, and three different claims look alike on paper. We explain each in our guide to what IS 10655 means for a steam hose.

Why working pressure and burst pressure on a steam hose are not the same number

Buyers sometimes read the larger number as the hose’s strength and the smaller one as a conservative suggestion. It works the other way round. Working pressure is the rating. Burst pressure is what the hose must survive in a laboratory before it is allowed that rating.

On our one braid grade the two figures are 10 BAR and 100 BAR. On the two braid grade they are 17 BAR and 170 BAR. In both cases the minimum burst is ten times the working pressure, and the chart below draws them to the same scale so the gap is visible.

Why such a wide gap? Because a steam hose that fails releases scalding steam and hot condensate into the space where people work, and because the hose ages. Every heat cycle, every bend and every drag across a floor takes a little from the wall. The margin between working and burst pressure is what keeps an older hose safe at its rated pressure, not spare capacity to be borrowed on a busy day.

Burst testing is a hydrostatic test, and the method is itself standardised: ISO 6134, the international specification for rubber steam hose, lists ISO 1402 on hydrostatic testing among its normative references (ISO 6134:2024 preview, clause 2). Hydrostatic pressure is one of the ten tests we run in our own laboratory, on equipment calibrated by NABL accredited bodies, and test certificates are supplied with every consignment.

For a buyer, the practical rules are short. Select the grade on working pressure and temperature, never on burst. Treat a spec sheet that prints only one pressure as incomplete. And if the single figure printed is large, ask which one it is before comparing it with another supplier’s working pressure.

The five details a supplier needs to quote a steam hose

Reading a spec sheet is half the job. The other half is giving the supplier enough to match a grade to your duty without a second round of emails. These are the five details we ask for on every enquiry. Four of them are numbers you can read off the plant.

1. Bore, in inches or millimetres

Give the nominal size, for example 3/4" or 20 mm. If you are replacing an existing hose and the marking has worn off, measure the inside diameter of a clean cut end. Do not measure the outside and convert, because the outside diameter changes with the number of braids.

2. Steam pressure at the hose, in PSI or BAR

This is the pressure where the hose actually sits. A plant with a 17 BAR boiler and a reducing station that feeds a cleaning point at 6 BAR needs a hose rated for the cleaning point, and saying “17” would push you into a heavier grade than the duty requires. Saying “6” when the hose is upstream of the station is the more dangerous mistake.

3. Steam temperature at the hose, and whether it is saturated or superheated

This is the line most enquiries leave out, and it is the one that most often decides the grade. Saturated steam at a known pressure has a known temperature. Superheated steam does not, so we need the temperature itself. If the duty is a condensate return rather than live steam, say so: continuous hot water is a different job from intermittent steam.

4. Total length in metres, and the number of lengths

“Fifty metres” can mean one coil or five assemblies of ten metres each, and those are quoted differently. Tell us whether you need cut lengths and how many. Coil lengths are not printed in our catalogue, so we confirm them with the quote rather than assume.

5. Coupling type and the delivery city

Tell us the coupling type or standard the hose will be fitted with, so the grade can be matched to its mean OD. We recommend interlocking or crimped steam couplings that grip the wire, sized to the mean OD; a worm-drive clamp on a barbed tail loosens as the wall expands and contracts with every heat cycle. The delivery city lets us confirm the dispatch and the lead time, which we give as a range with every quote.

A complete enquiry, written out, is five short lines. Here is an illustrative one, not a real order: “Bore 1". Pressure at hose 7 bar g. Saturated steam, about 170 °C. Four lengths of 10 m. Interlocking couplings both ends, delivery Pune.” From that we can confirm the grade, the size and the quantity, and send a written quote. Send yours through our contact page, by WhatsApp, or by email, and if your duty sits above 17 BAR or +232 °C, say so up front; we will tell you we have no published rubber grade rather than offer the nearest one.

Steam hose spec sheet red flags to check before you raise the PO

These are the gaps worth checking on any sheet, ours included. None of them proves a hose is unsafe. Each of them means the sheet has not told you something you need, and the fix is a single question to the supplier.

Two of these deserve a little more explanation.

• “Exceeds” is not “conforms”. “Exceeds”, the word we use, says the supplier’s figures sit above a standard’s type. “Conforms” says the hose meets every requirement of that standard. A BIS licence says the Bureau has allowed the maker to apply the Standard Mark, and BIS asks for the licence number to appear with the mark, preferably below it. If a tender asks for a BIS licensed steam hose, we do not hold one, and we will say so.
• The edition year matters for IS 10655. The BIS record lists IS 10655:2022 as the current edition and the 1999 edition as withdrawn (BIS, IS 10655:2022 record). If your tender cites the standard, check which edition and which type it names, and compare the supplier’s printed figures against it rather than the type label alone.