Laboratory Test Catalogue

This is the Bukan Pipe laboratory's own catalogue of test services, which the laboratory named as its reference in October 2026. For each test it gives the purpose, a summary of the method, the usual turnaround, the method standard and the requirement the product standard sets. Fees and exact lead times depend on the sample and the conditions and are stated in the quotation.

The accreditation table (equipment range per test) is on the test scope page, and what to send with a sample is on the services page.

The tests

Hydrostatic test (resistance to internal pressure)

Purpose: The key test for polyethylene pipe and other piping systems: whether the pipe survives a constant internal pressure at a set temperature for a set time.

Method: Three specimens with a free length of three times the nominal outside diameter are end-capped, placed in a water bath at the test temperature and held at the test pressure for the set time; the pressure–time graph comes with the report. A burst test, raising the pressure over a few minutes, is also offered.

Tensile test (tensile properties)

Purpose: Measures the tensile properties of the pipe, above all elongation at break.

Method: Dumbbell specimens are cut from the pipe to INSO 17140-1 and pulled at a set speed until they break.

Oxidation induction time (thermal stability, OIT)

Purpose: How long the stabilised polymer resists oxidation at high temperature — a measure of the antioxidant package.

Method: A small specimen from the raw material or the pipe bore is heated in the DSC to the test temperature; the atmosphere is switched to oxygen and the time to the onset of oxidation is recorded.

Carbon black content

Purpose: The carbon black left after pyrolysis of the PE sample; carbon black is what protects the pipe from sunlight.

Method: One gram of granules is weighed into a porcelain boat and pyrolysed in an electric furnace under nitrogen; the residue is weighed and the percentage calculated.

Carbon black dispersion

Purpose: Particle size of the carbon black and how evenly it is distributed in the pipe wall.

Method: Six thin slices from around the pipe are heated and pressed between glass slides and graded under the microscope against reference images.

Environmental stress crack resistance (ESCR)

Purpose: Crack growth in LDPE irrigation pipe under mechanical stress, as where a fitting is pushed onto the pipe.

Method: Specimens 20 nominal diameters long are bent and kept in a 10 % surfactant solution at the test temperature; after the set time they are inspected for cracks.

Charpy and Izod pendulum impact

Purpose: Impact strength of plastic pipe under a pendulum blow at low temperature.

Method: A cut piece of pipe is chilled for about an hour to the test temperature and then struck by the pendulum.

Melt flow rate (MFR)

Purpose: Melt behaviour of the polymer; a shift against the raw material points to degradation in processing.

Method: About 3 g of granules go into the heated barrel; under a set load the melt is extruded through the die, cut at set intervals and weighed.

Vicat softening temperature

Purpose: The temperature at which the specimen softens under a standard needle; a measure of heat resistance.

Method: A piece of pipe or fitting sits under a 1 mm² needle with a set load while the temperature rises at a constant rate until the needle penetrates 1 mm.

Resistance to dichloromethane

Purpose: The effect of dichloromethane on PVC pipe — an indicator of how well the material gelled in extrusion.

Method: A chamfered piece of PVC pipe is immersed in dichloromethane at the test temperature for 30 minutes and the surface is then inspected.

Density by immersion

Purpose: Density of non-cellular plastics.

Method: Three specimens of at least 1 g are weighed in air and in the immersion liquid; density follows from the difference.

Volatile content

Purpose: Volatile matter in polyethylene material.

Method: 25 g of sample is weighed into a glass dish and kept in the oven for 65 minutes; the mass loss is the volatile content.

Ash content

Purpose: Ash (mineral filler) in PVC; the same method is used for polyethylene pipe.

Method: Granules are weighed into a porcelain boat and burnt in the electric furnace; the mineral residue is weighed.

Pipe opacity

Purpose: The light that passes through the pipe wall; PP pipe and fittings must be opaque.

Method: A piece of pipe sits between the light source and the photocell and the transmitted light is read as a percentage.

Longitudinal reversion

Purpose: Length change of thermoplastic pipe after heating — a sign of residual longitudinal stress from extrusion.

Method: A 200 mm specimen is marked with two lines 100 mm apart, heated in the oven and re-measured after cooling.

Resistance to external blows (falling weight, clock method)

Purpose: Resistance of thermoplastic pipe to a falling weight.

Method: 200 mm pieces are marked with equally spaced lines and chilled; the striker is dropped from a set height onto each line and failures are counted.

Ring stiffness

Purpose: Ring stiffness of thermoplastic pipe — a buried pipe's resistance to flattening under soil load.

Method: Three 300 mm specimens are compressed between parallel plates at a constant rate and the force at 3 % diametric deflection is recorded.

Effect of heating on fittings

Purpose: The effect of heat on PVC fittings, which exposes moulding defects.

Method: Three fittings are kept in the oven for 30 minutes and inspected after cooling for cracks, delamination and distortion.

Dimensions and visual inspection

Purpose: Diameter, wall thickness and ovality of polymer pipe and fittings.

Method: Diameter with a circumference tape, wall thickness and ovality with callipers, compared against the standard's dimension tables.

System performance of pipe and fittings

Purpose: Performance of the assembled polyethylene system — pipe, fittings and valves together, not as separate parts.

Method: The system test set: hydrostatic at 80 °C / 165 h (INSO 12181), decohesion resistance (ISO 13954 and ISO 13955), ductility of the fusion interface (ISO 13956) and tensile strength of butt-fusion joints (ISO 13953).

Decohesion and crushing test on electrofusion joints

Purpose: Quality of the electrofusion weld on polyethylene pipe, above all in gas networks.

Method: A pipe–electrofusion fitting assembly (pipe two nominal diameters long each side) is crushed in the machine; the separated surface is examined and the ductile fraction determined.