Anti-corrosion protection of pipes and pipelines

Support, weld joint, flange — and another support: on a pipeline the vulnerable points repeat along the whole route, and rust usually starts there, on the underside of the pipe or under insulation. DQS protects steel pipes and above-ground pipelines on pipe racks, in plant buildings and in equipment piping across Uzbekistan against corrosion: we paint new lines and repair the coating on old ones. Hot and operating lines are painted without shutdown. We do not take on underground sections or soil-to-air transitions.

Weak points of a pipeline

• Supports and clamps: as the pipe moves with temperature, it rubs the coating off against the support, water is trapped in the gap, and none of this is visible from the side.
• Weld joints: on new lines they are left bare until testing — if they are not painted afterwards, rust will start there.
• Flanges, bolts, valves: paint goes on thin on edges and in crevices.
• Underside of the pipe: water runs down here, and on a pipe rack it is the hardest part to reach.
• Under thermal insulation: moisture gets in through damaged cladding, and the steel rusts unnoticed.

Why a pipeline is harder than a frame

Pipes run in tiers, several lines side by side, above roadways and equipment. We work from lifts, and where machinery cannot get through, certified industrial rope-access technicians go up.

• Before abrasive blasting we wash off oil and product and cover instruments and valves. Where blasting is prohibited, we clean by hand, as agreed with the client.
• The side of the pipe facing the neighbouring one, welds and edges are painted by brush: spraying leaves a thinner film there.
• We compare the pipe wall temperature, not the air temperature, with the dew point: a cold pipe “sweats” even in hot weather, and we never paint over condensation.
• We measure dry film thickness with DeFelsko PosiTector 6000 gauges around the entire circumference of the pipe, including the underside and joints. The results go into a report that stays with the client.

New line or repair

New pipes are best cleaned and primed before installation, with the joints and sling-damaged spots touched up after assembly and testing.

Repair starts with a walk along the route: we mark where the coating holds and where it has flaked or rust has crept under the film — and propose spot repair or repainting of the section. We feather the edges of the remaining coating and select a material compatible with the old one.

The coating system is set by the design; without a design we select it for the medium and the line temperature. We use paint systems based on abrasion-resistant epoxy coatings.

How many m² are in a pipeline

The area is calculated from the outer surface: 3.14 × outside diameter × length. For example, one kilometre of Ø219 mm pipe is about 690 m², and that volume already qualifies for the offer: 15% off on orders from 500 m². We will apply a trial area on your pipeline free of charge before the contract is signed. We give a warranty of up to 10 years on our work.

From our projects

Painting of pipes and pipeline assemblies — bends, tees, flanged pipes — and dry film thickness measurement.

Send us the design or a photo of the line to contact@dqs.uz and specify the diameters, length and operating temperature — we will convert linear metres into square metres and quote a price. Phone: +998 90 978 10 00.

See also: Anti-corrosion protection · Sandblasting · Polyurea waterproofing