LPS 1261 Issue 1.2 Requirements for testing flexible hoses for sprinkler systems

This Standard describes tests for the assessment of the suitability of flexible hoses to be used for sprinkler systems. Some installation codes may require these products to be supported or may even prohibit the use of these products.

Two types of flexibility are possible, 1 and 2

Type 1: hose of high flexibility. This may be used in applications where differential movement between the two ends is expected. (e.g. Supply to storage racks)

Type 2: hose of moderate flexibility. This may be used in applications where little or no differential movement between the two ends is expected after installation. (e.g. Supply to single sprinklers in suspended ceilings)

INFORMATION TO BE SUPPLIED BY APPLICANT

Prior to examination and testing an applicant shall furnish comprehensive information about the product for consideration. All documents shall be dated and given a reference number and issue description. If the applicant is not the manufacturer then an application must be accompanied by written permission for testing from the manufacturer.

The applicant shall supply the following detailed information relating to the product to be tested.

1. Manufacturing responsibilities:
   1. Name of manufacturer.
   2. Place of manufacture.

• Year of manufacture.

1. Relationship of applicant to manufacturer.
2. Company responsible for design and quality assurance.

1. Drawings of the components, including:
   1. Cross sections.
   2. General assembly.
2. Details of hose (formulation where applicable)
3. A description of any other materials of construction if not contained on the drawings.
4. Instructions and specification for installation / use including limitations and recommendations.
5. Whether the product or hardware are prototypes.

SPECIMENS TO BE SUPPLIED FOR TESTING

1. The applicant shall supply an agreed number of specimens.
2. When the product incorporates advances or changes in technology, then additional sample pieces, parts or sections may be requested for evaluation prior to the supply of the agreed specimens.
3. The number and size of specimens to be supplied for test is dependent upon the test schedule specified for the product type, size range and design variations
4. All specimens shall be supplied complete with specified fixings, seals for installation.

PRE-CONDITIONING

1. A) For Type 1 Flexible Hoses

Prior to each test the product shall be pre-conditioned by bending without pressure for 30,000 cycles in accordance with the following method:

For flexible hose assemblies up to and including DN 100, six samples of each nominal size shall be subjected to a fatigue test (see Figure 1). The test shall be conducted on the hose with the distance between the axis of the end fitting equal to twice the nominal dynamic bend radius given in Table 1.

The hose shall be subjected to repeated flexion at a rate of from 5 cycles/min to 30 cycles/min in a direction parallel with the axis of the hose through a movement of 2x.

The test shall be conducted using hose assemblies mounted to form a vertical loop as shown in Figure 1. The flexible length of the assembly l, shall be given in the following equation.

DN is the nominal size.

The hose shall not be lubricated prior to or during the test. Where the minimum bend radius specified is less than that stated in Table 1, the minimum bend radius shall be used.

Table 1 – Nominal size and bend radii (radii in millimetres)

1. B) For Type 2 Flexible Hoses

Prior to each test the product shall be pre-conditioned by bending through 10 cycles without pressure as follows:

For flexible hose assemblies up to and including DN 100, two samples of each nominal size of hose assembly shall be subjected to a bend test in accordance with Figure 2. With one hose end rigidly fixed, the other shall be moved in a circular arc around a former having a radius calculated form the nominal static bend radius as given in Table 1, until the hose assembly is in intimate contact with the full length of the arc of the former.

One stress cycle comprises one bend and the return movement to the straight position. The test shall consist of the assembly being flexed through 10 cycles without pressure as indicated in Figure 2. The test frequency shall be between 10 cycles/min and 30 cycles/min.

Where the minimum bend radius specified is less than that stated in Table 1, the minimum bend radius shall be used.

TEST REQUIREMENTS

 Examine each component for geometric and dimensional compatibility with the manufacturer’s drawings and each other where applicable.

Examine each component type for adequate identification. This shall include: Manufacturer’s name, Hose type (1 or 2), size of component, pressure rating, temperature rating and LPCB reference. Normally the marking shall be printed on the product but labels can be used where this is not possible.

• Check that the components shall maintain structural integrity and shall not leak when subjected to a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 1 hour. This test is to determine whether jointing materials/adhesives are weakened by creep.

7.7. Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 5 minutes -0, +30 seconds after the following conditioning:

• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 5 minutes -0, +30 seconds after conditioning in sulphuric acid in accordance with clause 8.4 of BS 3506/clause 4.2 of BS 4346.
• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 5 minutes -0, +30 seconds after immersion in bleach for 30 days at 20°C ± 5°C. There after test to destruction to determine whether the hose or fittings had been weakened. This Clause shall not be performed on stainless steel pipes.
• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 5 seconds -0, +30 seconds after conditioning in acetone when tested in accordance with clause 8.3 of BS 3506.
• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, after exposure to normal daylight for 90, 180 and 360 days. This Clause shall not be performed on stainless steel pipes.
• Record change of state of materials after subjecting the components to impact utilising clause 9.2 of BS 3506. Each diameter/size shall be subjected to this test.

This Clause shall not be performed on stainless steel pipes.

• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar for whichever is the greater, after completion of the crushing test described below:

The flexible connection with the cover removed shall be subjected to a crushing load of 100kg applied evenly over a length of 50mm for 30s. The connection shall not collapse or show signs of permanent deformation in excess of 5% of any appropriate dimension measured before the test.

• At least one flexible hose of each product range shall be subjected to salt spray conditioning in accordance with BS EN 60068-2-52:1996 Test K6 Salt Mist Cyclic (Severity 1).

On completion of the salt spray conditioning, the assemblies shall be subjected to the hydrostatic pressure test of 7.4. No leakage shall occur. The conditioned assemblies shall be dismantled and examined for the effects of the corrosion.

• Check that the components shall maintain structural integrity and shall not leak at a pressure four times the maximum working pressure ±1 bar or 48 bar, whichever is the greater, for 5 minutes -0, +30 seconds after completion of the SO2 conditioning below:

Dry Pipe Fire Test

• The test is to be carried out indoors. A flexible hose assembly shall be configured as in Fig. 1. The flexible hose assembly shall be pressurised with air to 3 bar +0.5 bar/-0 bar for 3 minutes. The flexible hose assembly shall then be subjected to a fire test. The air pressure shall be kept constant by venting.

Within 60 seconds of initiation of the test a temperature of 800°C ± 50°C shall be achieved 13mm-15mm from the surface of the flexible hose. An average temperature of 800°C shall be maintained around the flexible hose for a period of at least 6 minutes.

• 7 min +30s/-0s after the start of the test the fire tray shall be removed and the assembly shall be filled with cold water and pressurised to 8 bar ±1 bar for 2 min ±30s/-0s.
• After the water pressure test the assembly shall be dissembled and visually examined for evidence of fire damage and/or distortion that may affect the integrity of the assembly.
• The flexible hose shall satisfy the following requirements:
  1. The flexible hose must maintain the integrity of the pipework throughout the test but the seals can leak.
  2. There shall be no visual evidence (excluding heat and smoke discolouration) of fire damage and/or distortion of those flexible hose components, which assist in maintaining the integrity of the pipework.

7.19 Assess the effect of reaction forces on a typical pipe work installation upon activation of a sprinkler head. Install an appropriate water supply and connect a flexible hose terminating in a sprinkler in a suspended ceiling. The longest flexible hose under test with the maximum number of bends allowed by the manufacturer shall be installed in accordance with the manufacturers instructions. Where the product is designed to connect up to a sprinkler in a suspended ceiling, the suspended ceiling shall consist of one fire rated tile 600mm x 600mm.

Then subject the installation to an internal standing pressure of 12bar ± 0.5bar, and operate the sprinkler. Maintaining a running pressure of 11 bar ± 0.5bar for 2 min and record observations of the effect of the discharge. The sprinkler head must remain in position.

The pressure loss through each length of hose with the maximum number of bends shall be determined and the equivalent length of steel pipe calculated by the manufacturer and supplied to the test house.

PIPE SUPPORTS

Note 1.            Flexible length is 0.5m or minimum possible whichever is the greater.

Note 2.            Pipe shall be grooved or screwed at one end and, as appropriate, shall have a pressure / leak tight blank at the other end or a suitable fitting which can be adapted to ISO 7/1-Rp 1.

Note 3.            Provision shall be made for:

1. Pressure charging connection.
2. Pressuring monitoring.
3. Vent valve.

Note 4.             The flexible assembly shall be supported as shown. The flexible shall be positioned over the centre of the fire test tray.

Note 5.            For temperature monitoring, four thermocouples shall be placed at various places within 13mm to 15mm of the flexible assembly, level with the horizontal centre line.

Note 6.            For wet pipe test a band should be placed around the fire test tray to contain fire overspill and safety precautions observed.