Quality and test specifications for multiply fabric expansion joints

(1) Suitable insulation in the form of nonwovens, felts and wovens consisting of e.g.:
– glass fibres,
– ceramic fibres,
– silicate fibres.
(2) Suitable coatings and sealing layers are e. g.:
– nitrile rubber (MBR),
– chloroprene (CR,
– chlorosulphonated polyethylene (CSM),
– butyl rubber (IIR, C II R, B II R),
– ethylene propylene terpolymer (EDPM),
– fluorcarbon rubber (FPM),
– silicon rubber (O),
– polytetrafluoroethylene (PTFE).
(3) Suitable supporting layers in the form of knitted or woven abrics consisting of e. g.:
– polyester,
– aramide,
– glass,
– stainless steel.
All the materials used by the manufacturer must be listed on the material data sheet. The manufacturer’s specifications, e. g. in his leaflets, must be in accordance with the data on the material data sheet.

(1) An identifiable material designation
(2) The permissible maximum temperature
– in continuous operation,
– under critical load,
A critical load is defined as a non-recurring rise in temperature and/or pressure for a maximum duration of 15 minutes only once in the lifetime.
(3) Resistance to chemicals
is only relevant for the area in contact with the process media. It can be quoted by reference e. g. to the DECHEMA Material Table.
Where individual specifications of chemical resistance are issued with respect to special media, it is necessary to quote the acting medium, its concentration, its temperature, and its duration of action.
(4) Mechanical strength
is conditional on the supporting layers. It can be quoted in terms of tensile strength or maximum stress.

The production data sheet must list the same materials used for the fabric expansion joint as are specified in the material data sheet.
It must include at least:
– the materials used,
– the design,
– processing instruction,
– dimensional specifications.

A multiply fabric expansion joint, which is designated as Nekal®-tight, must contain one or more sealing layer/s that is/are Nekal®-tight under the service conditions specified in the manufacturer’s data sheet. And the Nekal®-tight finish also applies to the seam splice and clamping areas of the sealing layer.
A Nekal®-tight expansion joint must be tight in the clamping area according to EN 1593 and TI-003 when using the fastening method and the flange surface specified by the manufacturer.

The test must be based on DIN 53508. The test period shall run for 28 days at the continuous service temperature specified for the materials.
After the thermal loading, the tensile strength of the layers must not have fallen below 50 % of the initial value. The tensile strength of the reinforcing layers must be tested in accordance with EN ISO 13934-1.
After the thermal loading, the Nekal®-tight sealing layers must be leak-proof as defined by the leak test (Section 3.2.6).

The resistance to chemicals must be tested in accordance with the specifications in the material data sheet. Details concerning the specific application must be discussed with the independent test centre so that they can be taken into account in its testing.
The test period shall run for 28 days. After the test, the sealing layers designated to be Nekal®-tight must still be leak-proof as defined by the leak test (see Section 3.2.6).
The tensile strength of the reinforcing layers must not have fallen below 50 % of the initial value.

The leak test must be carried out according to EN 1593 and TI-005.
At a test pressure of one and a half times the nominal pressure, but at least 50 hPa, no bubbles may appear.

Technical Information TI-005

The specimen must consist of sealing and reinforcing layers in conformance with the selected expansion joint structure and be at least 100 mm wide. The samples used in this case do not have a notch.
The frequency shall be equal to 1 Hz.
A total of 10.000 cycles must be reached without any signs of damage.