Neometrix / Materials & Pressure Test Equipment / Pipe Hydrostatic Pressure Tester / NMX-PHT-79

NMX-PHT-79 · ENGINEERED-TO-ORDER CLASS — SPECIFY · SIZE · BUILD · CALIBRATE · RUN · PROVE

Pipe Hydrostatic Pressure Tester. Hold it still; read the clock.

Name: Pipe Hydrostatic Pressure Tester
Brand: Neometrix
SKU: NMX-PHT-79

A pipe hydrostatic pressure tester fills a plastic pipe with water, holds it at a set pressure in a bath at a set temperature, and records how long it lasts. The result is not a pressure. It is a time.

So the tester has to hold the pressure still while the pipe creeps, hold the temperature still, and stop the clock for each specimen the moment it fails.

Discuss a pipe hydrostatic tester Capability note (PDF)

A multi-station pipe hydrostatic tester on a plain white studio background: a long low stainless steel water bath on a pale grey steel frame holding six short lengths of smooth blue plastic pipe side by side, each closed with a bright steel end cap at both ends and fed by a thin stainless tube from a stainless manifold block with six small valves at the back edge, a grey cabinet and a small stainless reservoir at the right end, and no people

Fig · 01 — A multi-station pipe hydrostatic tester: six lengths of pipe in a water bath, each fed from a manifold, with a reservoir and a cabinet at the end — illustrative render.

The result

a time to failureat a constant pressure and temperature

The pressure

held, not just reachedmake-up water as the pipe creeps

The bath

a set temperaturewater in water, or water in air

The clock

one for every stationeach failure stops its own timer

Status

engineered to orderno pipe tester claimed

ISO 9001ISO 14001ISO 1167 and ASTM D1598 reference standards

Overview

Why the whole job is the clock.

Because a plastic pipe does not fail at a pressure. It fails after a time, and the time depends on the pressure and the temperature.

One test station of a pipe hydrostatic tester on a plain white studio background: a short length of smooth blue plastic pipe resting on two bright steel saddle supports on a stainless base plate, closed at each end with a bright steel end cap, with a thin stainless tube rising to a small ball valve and a cylindrical pressure transducer with a short black cable, and no people

Fig · 02 — One test station: a length of pipe closed with end caps on two saddles, fed by a tube through a valve to a pressure transducer — illustrative render.

Hold it still; read the clock.

What the tester is for

It tests plastic pipes, fittings and assemblies by internal water pressure. It suits a multi-station constant-pressure tester with a bath, a short-time burst tester, and a combined machine that does both. Each specimen is closed with end caps, filled with water and held at its own pressure.

Why the result is a time

A thermoplastic pipe under steady pressure creeps, and in the end it fails: it balloons, bursts or weeps. How long that takes depends on the pressure and the temperature. The test records that time. Run at several pressures, the times are the basis for estimating long-term strength.

Why the pressure has to be held

A plastic pipe is not rigid. Under pressure it expands, and the volume of water inside grows. If nothing tops the water up, the pressure falls. So the tester feeds make-up water to hold the set pressure while the pipe creeps, and it reads the pressure as well as setting it.

Why the temperature has to be held

Heat speeds the creep. A bath holds the specimen at a set temperature, either water in water, with the bath round the specimen, or water in air, with the specimen in a heated chamber. Either way the temperature goes into the record next to the time.

Why each station keeps its own clock

Specimens do not fail together. When one fails, its station has to close, stop its own timer and leave the others undisturbed. A single clock for the whole machine would lose the answer for all but the first.

Why the air is bled out

Air in a specimen is compressible. It makes the pressure harder to hold, and it stores energy that a failure then releases. So the specimen is filled with water and the air is bled out before it is pressurised.

Why the short-time burst test is separate

The short-time test asks a different question: at what pressure does the pipe fail in a short time? It needs a smooth, fast ramp and not a long hold, so it is a different mode of the same machine.

The method

Specify, size, build, calibrate, run, and prove.

Six steps in a fixed order. Showing that the pressure holds while a specimen creeps, and that the air is out before the clock starts, are the two a quick order skips.

1 · Specify

The pipes, fittings and assemblies, the pressures, the temperatures and the number of stations are stated by the customer or by the method they name.

2 · Size

The make-up water supply is sized for the expansion of the largest specimen, and the bath and the stations for the number of specimens that run together.

3 · Build

The stations, the manifold, the pressure control, the bath and the controller are built as one installation.

4 · Calibrate

The pressure transducers, the temperature probes and the timers are calibrated, so that the time and the conditions it was measured under each have a record of their own.

5 · Run

A trial specimen is run first, to show that the air comes out, that the pressure holds as the specimen creeps and that a failure stops only its own station.

6 · Prove

A record is kept for every specimen, with its pressure, its temperature and its time, and handed over with the machine.

Which test for which question

Test	What it answers	What to watch
Constant pressure at a set temperature	how long the pipe lasts under steady pressure	the pressure has to be held while the pipe creeps, the temperature steady, and every failure timed on its own
Short-time burst	at what pressure the pipe fails in a short time	a smooth, repeatable ramp, and a guard that contains the failure
Water in water or water in air	which bath puts the specimen at the right temperature the right way	water in water holds the temperature most evenly, while water in air is simpler to reach into and needs circulation
Fittings and assemblies	whether the joint lasts as long as the pipe	the end caps and fixtures must seal without loading the joint in a way the test does not intend

The step people underrate is holding the pressure. A tester that reaches the set pressure and then lets it sag as the pipe creeps is timing a different test from the one the customer asked for.

Work content

What the tester contains, element by element.

Read it as a checklist: a tester missing a row will pressurise a pipe and give a number, but not a time you can defend.

A short-time burst test station on a plain white studio background: a clear polycarbonate guard box with bright aluminium corner frames and its hinged lid open, standing on a pale grey steel base and holding a short blue plastic pipe closed with a steel end cap at each end, a thin stainless tube leaving the guard to a plain grey pump unit beside it, and no people

Fig · 03 — A short-time burst station: a pipe closed with end caps inside a clear guard with its lid open, fed from a pump unit beside it — illustrative render.

Element	What it does	What matters
Test stations	each hold one specimen	end caps that seal the specimen without adding a false load, an isolating valve, and its own pressure sensor and timer
Water supply and make-up	fills the specimen and tops it up as it creeps	a pump or intensifier and a reservoir sized for the expansion of the largest specimen, with a smooth control so that the pressure does not hunt
Pressure control	holds each set-point	a control for every station, tuned to the stiffness of the specimen, so that one station never disturbs another
Bath or chamber	holds the temperature	a bath of water or a heated chamber, with circulation so that the temperature is the same round every specimen, and a probe whose reading goes in the record
Air bleed	takes the air out	vents at the high points and a filling sequence that leaves the specimen full of water
Failure detection	stops the clock	a drop in pressure or a rush of make-up water tells the station that its specimen has failed, and its timer stops and its valve closes
Burst mode	runs the short-time test	a controlled pressure ramp to failure and a record of the pressure reached, behind a guard
Controller and recorder	runs the tests	sets every station, logs pressure, temperature and time for each, and writes a record for every specimen
Safety guards	protect people	a guard round the stations and the bath, interlocked, with an emergency stop and a drain
Procedure	fixes the sequence	specify, size, build, calibrate, run and prove, the same for every tester
Testing & documentation	prove the tester first	a trial specimen run, the pressure held as it creeps, a failure that stops only its own station, and a record the customer can inspect

The elements that decide whether the time is true are the make-up water and pressure control and the bath, and the one that decides whether every failure is caught is the failure detection. The first two hold the conditions, and the third reads the clock.

Full specification — expand

System	Test stations that each hold one plastic pipe, fitting or assembly closed with end caps and filled with water; a pump or intensifier and make-up water supply with a pressure control for every station; a bath of water or a heated chamber that holds the temperature, with circulation; high-point vents to bleed the air out; a timer, a failure detector and an isolating valve for every station; a short-time burst mode with a controlled pressure ramp behind a guard; a controller and recorder that log pressure, temperature and time for every specimen; guards, interlocks and an emergency stop; a written test plan; and calibration, testing and documentation before handover
The One Idea	Hold it still; read the clock.
Why The Result Is A Time	A thermoplastic pipe under steady pressure creeps and in the end fails by ballooning, rupture, seepage or weeping, and how long it takes depends on the pressure and the temperature, so the test records the time to failure at a constant pressure and a constant temperature
Why The Pressure Is Held	A plastic pipe is not rigid: it expands under pressure, the volume of water inside grows, and with no make-up water the pressure falls, so the tester feeds water to hold the set pressure while the pipe creeps and reads the pressure as well as setting it
Why The Temperature Is Held	Heat speeds the creep, so the specimen is held at a set temperature in a bath, water in water or water in air, and the temperature goes into the record next to the time
Why Each Station Keeps Its Own Clock	Specimens do not fail together, so when one fails its station closes, stops its own timer and leaves the others undisturbed
Why The Air Is Bled Out	Air in a specimen is compressible, so it makes the pressure harder to hold and stores energy that a failure then releases, and the specimen is filled with water and the air bled out before it is pressurised
Standards	ISO 1167 is the public general method for the resistance of thermoplastics pipes, fittings and assemblies to internal hydrostatic pressure at a given temperature, ASTM D1598 covers the time to failure of plastic pipe under constant internal pressure, ASTM D1599 covers short-time hydraulic failure pressure, and ISO 9080 covers the extrapolation of long-term hydrostatic strength. This page prints none of their pressures, temperatures, times or limits, and no edition year: those come from the method the customer names and from the pipe. Approval of a pipe, or of a test result, rests with the customer and the authority they name; none is claimed here
Configurations	A multi-station constant-pressure tester with a bath, a short-time burst tester, and a combined machine that does both
Scope Boundary	This page is the pipe hydrostatic pressure tester. It is not a hydrostatic test bench, which proves compressed gas cylinders (see hydrostatic test bench), not an impulse and load test rig, which cycles the pressure on hoses and fittings (see impulse and load test rig) and not a hose test bench, which proves hydraulic hoses (see hose test bench). A pipe fatigue rig and a leak test rig are different equipment again. No certification is claimed here
Status	Neometrix engineers pipe hydrostatic pressure testers to order, and no delivered pipe hydrostatic pressure tester is claimed.

Configurations

One method, three ways to build the tester.

The method, the make-up water, the bath, the clock for every station and the record are shared. What changes is how many specimens run together and which question is asked.

Multi-station constant-pressure tester

Many specimens, each with its own clock

Several stations in one bath, each holding its own pressure and stopping its own timer, for the time to failure of pipes, fittings and assemblies.

Short-time burst tester

One specimen, one smooth ramp

One station behind a clear guard, with a controlled pressure ramp to failure and a record of the pressure reached.

Combined machine

Both questions in one installation

Constant-pressure stations in a bath and a burst station on the same pump, control and record.

And the part that is not equipment at all, yet decides all three: the test plan. It fixes the pressures, the temperatures, how many specimens are run at each and what is recorded. It is written from the pipe and the method the customer names, not from the tester.

Where it is used

Wherever a pipe is rated for years, and the rating has to be earned in weeks.

The common thread is a plastic pipe that will sit under pressure for a long time, and a test that has to say how long before it is laid.

Pipe and fitting makers

Where each production lot is checked and new compounds and designs are proved.

Plastics testing institutes

Where pipes and fittings are tested to a named method for makers and buyers.

Water and gas utility laboratories

Where pipe lots are tested before they are laid.

Research laboratories

Where new materials are compared by the time they last under steady pressure.

Watch

See it in motion.

A short walkthrough video of the pipe hydrostatic pressure tester.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 What does a pipe hydrostatic pressure tester actually do?

It holds plastic pipes, fittings or assemblies under internal water pressure, in a bath at a set temperature, and records how long each lasts. Each specimen is closed with end caps, filled with water, vented of air and brought to its own pressure. The tester then holds that pressure, feeds make-up water as the specimen creeps, and stops a separate timer the moment the specimen fails. A burst mode asks the short-time question instead. It does not decide whether a pipe passes: that is the job of the method and of the people who name it.

Q · 02 Why is the result a time and not a pressure?

Because a thermoplastic pipe does not have one failure pressure. Held at a steady pressure it creeps, and after a time it balloons, bursts or weeps. The lower the pressure, the longer it lasts, and heat shortens it. So a test asks how long the pipe survives at a chosen pressure and temperature, and a set of such times at different pressures is the basis for estimating how it will behave over years. The pressure and the temperature are therefore conditions to be held, and the time is the result.

Q · 03 How is the pressure held constant while the pipe creeps?

By feeding water. A plastic pipe expands under pressure, so the volume inside grows, and if nothing makes it up the pressure falls. Each station has a pressure sensor and a control that adds water as the specimen expands, from a supply sized for the largest specimen. The control has to be smooth, so that it does not hunt and disturb the specimen, and it must not lean on the other stations. The tester also records the pressure it actually held, so the record shows the test that was run and not only the one that was set.

Q · 04 Should the bath be water in water or water in air?

It depends on the method and the pipe. Water in water puts the bath round the specimen and holds the temperature most evenly, which is why it is common for long tests. Water in air puts the specimen in a heated chamber, which is simpler to reach into and to look at, but it needs good circulation so that the temperature is the same round every specimen. Whichever is chosen, the temperature probe is read for every run and its reading goes in the record. We set out the trade-offs against your pipes before we propose a bath.

Q · 05 Is this the same as the hydrostatic test bench, the impulse and load test rig or the hose test bench?

No, and the differences are worth stating precisely. The hydrostatic test bench page covers the proof-pressure test of compressed gas cylinders. The impulse and load test rig page covers cycling the pressure on hoses and fittings. The hose test bench page covers proving hydraulic hoses. This page is the pipe hydrostatic pressure tester. A pipe fatigue rig and a leak test rig are different equipment again. It does not replace any of them, and it does not claim what they claim a second time.

Q · 06 Has Neometrix built one of these?

We would rather answer this plainly than let a page imply otherwise. Neometrix engineers pipe hydrostatic pressure testers to order, and no delivered pipe hydrostatic pressure tester is claimed. What stands behind the offer is adjacent: Neometrix engineers a hydrostatic test bench (see the hydrostatic test bench page), an impulse and load test rig (see the impulse and load test rig page) and a hose test bench (see the hose test bench page). The pumps, valves, transducers, baths, heaters and controllers are catalogue items, bought in, not invented. What Neometrix engineers is the tester around them: the stations, the end-cap fixtures, the make-up water and pressure control, the bath, the timers, the guards, the procedure and the test plan. So the honest position is that the tester is engineered to order, the neighbouring disciplines are in the building, and the first tester of this exact kind will be built around the customer's own pipes rather than taken off a shelf.

Q · 07 Which standard applies, and what can the tester not do?

ISO 1167 is the public general method for the resistance of thermoplastics pipes, fittings and assemblies to internal hydrostatic pressure at a given temperature. ASTM D1598 covers the time to failure of plastic pipe under constant internal pressure, and ASTM D1599 covers short-time hydraulic failure pressure. ISO 9080 covers the extrapolation of long-term hydrostatic strength from tests of this kind. This page prints none of their pressures, temperatures, times or limits, and no edition year: those come from the method the customer names and from the pipe. The tester holds conditions and keeps a record. It does not certify a pipe: this page claims no certification or accreditation. No pressure, temperature, time, size or quantity figure is printed here, and approval for use rests with the customer and the authority they name; none is claimed here.

Q · 08 What do you need from us to quote?

Six things, and most of them describe your tests rather than the tester. First, the specimens: pipes, fittings or assemblies, their size range and their material. Second, the pressures you need to hold, and the range you want to burst to. Third, the temperatures and the kind of bath you prefer. Fourth, the stations: how many specimens you want to run together. Fifth, the method you name. Sixth, the record: what you want kept for every specimen. From that we come back with a tester concept, a written test plan you can check, and a budgetary price.

The neighbouring pressure test pages, and how they differ from this one.

Three neighbours: one proves gas cylinders, one cycles the pressure, one proves hoses.

↗ Gas cylinders

Hydrostatic Test Bench

A proof-pressure and leak test for compressed gas cylinders - one proof at a set pressure, where this page holds a pipe under pressure until it fails.

↗ Cycling the pressure

Impulse and Load Test Rig

An endurance rig that cycles the pressure on hoses and fittings - the pressure changing again and again, where this page holds it still.

↗ Hydraulic hoses

Hose Test Bench

A bench that tests hydraulic hoses for pressure, durability and safety - a hose under hydraulic duty, where this page tests a plastic pipe for time.

Browse all Neometrix product lines.

Get a quotation

Tell us the pipes, the pressures,
and how long they must last.

The projects desk replies within two working days with a tester concept, a written test plan you can check, and a budgetary quotation. Write to [email protected] or use the form.

Enquire — pipe hydrostatic tester Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — PIPE HYDROSTATIC PRESSURE TESTER SPECIFY · SIZE · BUILD · CALIBRATE · RUN · PROVE — HOLD IT STILL; READ THE CLOCK ENGINEERED IN NOIDA · INDIA