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STOPAQ® Products » Application: Coating of Above-ground Flanges

Above-ground flanges can be rapidly, effectively and simply protected against corrosion with the STOPAQ® System.

Safety and technical data sheets for the material to be applied

Preparations

  1. The pipe-piece to be coated must be excavated sufficiently so that it can be handled on all sides.
  2. Excavate 0.3m under the lowest pipe part.
  3. The working area must be kept dry during application.
  4. Check regularly whether the pipe stays above dew point by means of a dew point gauge.
  5. Drain (if necessary).
  6. Keep free from rain, but provide sufficient ventilation with regard to dew point.

Base surface quality

The part of the pipe where the coating all around has to be removed, is the length of the flange rim + 150mm (L1 + 150mm).

Clean the space between the flanges with compressed air and dry.

The old damaged coating must be removed all around from the flange faces and the pipe. Clean as thoroughly as possible. The surface to be coated must be clean and dry and free of loose parts. This can be achieved by brushing to St 2, and when persistently dirty it must be grit-blasted to Sa 2.5.

To prevent damage to the seal during grit-blasting, apply a temporary rubber string between the flange faces.

At the point of connection to the bitumen/PE, this must be bevelled under an angle of 30°. The bitumen between the two connecting spots must be removed entirely. The bitumen coating, where the final layer is applied, should be dry-burned carefully with a non-soothing burner. The base surface must be dry and clean. Should irregularities be found on the pipe around the repair spot, then management must be consulted.

If the coating consists of asbestos bitumen, the applicable regulations for removal must be followed.

Summary

Prior to application, check:

Flanges and surrounding temperature

The flanges and the pipe part to be coated should be heated to approx. 45°C by applying thermic band heating. However, do not use band heating for pre-heating welding activities. This raises the temperature too high, and the adjacent paintwork may be burned.

Application of STOPAQ® FN 4200 between the flange cheeks

First apply 2 strips of painter’s tape on the rims of both flanges. This is to clean the rims for the next application after coating with STOPAQ® FN 4200. By using a pneumatic kit pistol with the help of the correct accessories (long flexible spray nozzle), the entire flange space is filled fully by spraying STOPAQ® FN 4200 from inwards to outside. It is important to use the flexible spray nozzle, because this can fill very small spaces.

After filling, the redundant paste is removed with a putty knife and smoothened equally to the flange rims. Now the painter’s tape can be removed and the surroundings are clear.

Application of STOPAQ® Wrappingband CZ (H) on the pipe part

If applied properly STOPAQ® Wrappingband CZ (H) provides long-lasting corrosion protection to the adjacent pipe. STOPAQ® Wrappingband CZ(H) must be at a temperature between 40°C and 45°C, for optimal application of the product..

If there are any sharp pieces on the weld and/or redundant weld pieces, STOPAQ B.V. recommend to grinding it and/or put an extra tape over the welds.

The first wrapping must be applied tightly to the existing coating on the brushed base surface. Then wrap with minimum 10mm overlap tightly to the flange face. An extra wrapping is then applied on the transition of the existing coating, and in such a way that it is overlapped by 5cm.

Application of STOPAQ® CZ H Paste on the flanges

Apply the STOPAQ® CZ H Paste under an angle of approx. 45° on the outside of the flange and pipe. See to it that the bolt ends are fully covered.

The bolts and nuts are covered by a layer of STOPAQ® CZ H Paste. Spread the STOPAQ® CZ H Paste in a bulbous shape, and clean the outer flange rims as thoroughly as possible. If the thickness of 20mm STOPAQ® CZ H Paste is exceeded because of the flange size, immediately apply cord-bandage of STOPAQ® Wrappingband CZ H . After this a next layer of STOPAQ® CZ H Paste can be applied.

Application of STOPAQ® Wrappingband CZ H on the outer flange rim

Further, apply minimum 1 wrapping STOPAQ® Wrappingband CZ H on the outside of the flange and in such a way that the nuts- and bolt ends (which are under a layer of STOPAQ® CZ H Paste) are extra protected by the STOPAQ® Wrappingband CZ H . The last wrapping is 100mm overlapped.

Application of STOPAQ® Wrappingband CZ H entirely

When applying STOPAQ® Wrappingband CZ H start lengthwise (1). Application is done with 30mm overlap. Finish squarely so that a firm connection is made.

Application of STOPAQ® Polyester

An extra mechanical protection can be provided as follows (the applicator must have the required certificate):

Application of STOPAQ® Polyester : Method 1

STOPAQ® Polyester is a 1-component polyester mat, which will harden by exposing it to UV-light. Do not expose this product to sunlight during application. Protect against sunlight while unpacking and cutting to size. Mind the minimum temperature (10°C).

The overlapping of the polyester mats is 50mm. Roll the overlapping tightly with a roller. Please follow sequence as described above when applying, i.e. first strips lengthwise, then apply some strips squarely to achieve the cross layers.

Application of STOPAQ® Polyester : Method 2

Another method is a ready-made cartridge. However, bear in mind that polyester must always have sufficient overlap on own material. This can be done by applying an underlying wrapping of polyester mat first on those spots, where the material will not cover each other after application (A). The next layer will then have sufficient cover of the underlying layer.

During application and hardening absolutely no water may come on the product and it must be entirely above dew point. Also it may not be mechanically charged/ loaded in any way.

Hardening

UV lamps must be used for hardening. Daylight contains UV-A light, but due to fluctuations of weather conditions, the presence of UV-lamps is obligatory. The UV-light can be reflected by means of aluminium foil on the underside. The intensity of the UV-light determines the speed of hardening. Knock to check whether the polyester has hardened.

Painting

After hardening the product can be painted with an appropriate PU coating.

See Also

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