Corrosion has always been a challenge to chemical process industry. This is inevitable multifaceted problem, covering chemical corrosion of reaction vessels, pumps, pipes & fittings, valves and other equipment used for measurements and process control.

The damaging effects of corrosion and/or the pre-emptive steps to control them both impose a heavy burden on the resources of the industry. Apart from the direct loss of parts or the loss of functional ability of the system, corrosion also causes severe safety and pollution hazards in the form of gas or chemical leaks from the affected parts. Such accidents may further lead to very heavy consequential losses and expenses. Therefore, the golden rule - ‘Prevention is better than cure’ - is very much valid when dealing with the corrosion related problems.

The structures and equipment, expected to give long-term services, are chosen with sufficient corrosion allowance and suitability to all types of chemicals at the maximum temperature and pressure conditions envisaged by the particular industry. They, therefore, require a much higher initial capital investments compared to piping products. Piping products used for transport of different chemicals also require the same degree of corrosion resistance and service dependability. However, the piping system usually requires frequent modifications and changes at short intervals to suit the current end product’s manufacturing cycle in a particular industry. It is now statistically well established that the plastic lined steel piping system gives the maximum flexibility for changing / rerouting the pipelines due to their bolted flange connections.

Wood and glass, despite their poor mechanical strength and short service life, were the first choice for corrosion resistant piping. Rubber and Lead provided further improvements in mechanical strength and better life. Later, these materials were used for lining of steel parts to get further improvement in performance of piping products. Despite the problems with their usage, they are still in use in the process industry for historical as well as subjective reasons.

Plastics have excellent corrosion resistance properties comparable to glass and ceramic. They have good mechanical strength and easy process-ability to form shape and size.

Simple commodity Plastics like Polyethylene (PE or HDPE) and Polypropylene (PP) are produced in large quantities. They have the unique property by which they do not get dissolved in any known industrial solvent either organic or inorganic. The Fluoropolymer Plastics like PTFE, PFA, FEP, ETFE, PVDF etc. have superior corrosion resistance to practically all the chemicals & solvents; and that too at a higher temperatures ranging up to 250 degrees Celsius.

All these plastics are being used for piping products in every chemicals industry.

Though plastics have sufficient mechanical strength at room temperature, it gets reduced by the service conditions, which causes their swelling, softening and weakening of the polymer bonds within.

All the plastics are affected by the phenomenon of creep, i.e. they slowly loose their strength, shape, size, form, rigidity etc. over a time-period, under the combined influence of structural stresses, internal pressures, service temperatures and the atmospheric temperature cycles. Ultra Violet Radiation in the sunlight also affects the plastics.

These factors, thus, restrict the use of the bare plastic products for piping. The bare plastic pipelines are very frequently distorted and deformed due to expansion and sagging.

To construct a plastic pipeline for chemical transport, necessarily involves welding of flanges, stub ends, cut sections of pipes to fabricate the elbow bends, tees, reducers and crosses. Two methods are used - hot gas + filler wire and hot mirror butt-welding. These weld joints are the most vulnerable spots for frequent & abrupt failures of the pipeline in service.

Even the best weld joint made under ideal conditions or on a dedicated machine can have only the 80 % efficiency compared to the extruded pipe material, assuming full area contact exists on the butting faces. At site this is very difficult to achieve consistently. Therefore, the joint efficiency hardly ever reaches a 50 % strength and performance level compared to the basic plastic pipe. The weld joints also have internal upsets which reduce the bore at those spots and become the 'speed-breakers' for the smooth flow of the chemical.

Chemically - especially in the presence of solvents - these welds are affected by the faster absorption/permeation and consequently loose the weld bond strength. Even otherwise, when the weld joints are structurally stressed in tension, the butt joints may abruptly fail. This happens due to thermal expansion of the linear pipes, which gets accumulated near the stub ends and/or in the elbows and tees at the turning points of the pipeline, in spite of the mandatory rigid steel supports.

To improve the structural strength Glass Fiber - Epoxy Coatings are being used very commonly, but they only marginally improves the service life.

The linear expansion of the plastic pipeline - due to temperature and/or solvent absorption - is unavoidable and it may at times crack open the FRP reinforcement. The weld joints within also fail at times.

The chemical or vapour leak from the PP Piping travels along the pipe till it finds a weak spot in FRP Coat to ooze-, drip- or liberally flow - out. The local FRP repair causes it to shift to a different location. Unless the leaky PP joint is located it cannot be stopped, but by then the entire FRP Coating in between may have to be opened up.

Therefore, the FRP reinforcement of the Plastic piping leads only to an illusionary strength, but surely becomes a positive nuisance to the user in a short time.

The mechanical and structural strength of the steel pipes gives the rigid, safe and reliable pipeline. The Plastic pipes are excellent for transporting the corrosive media. Combining their strengths is the logic behind the design of the Plastic Lined Steel Piping Products.

Therefore, to get a composite product - internally corrosion resistant and externally having steel strength - the plastic pipe is put inside the metal pipe. This takes care of all the problems in one stroke except for the plastic weld joints.

To avoid the welds in plastic pipes, the flanged joints are made use of. The internal plastic pipe is flared on the steel flange face using a special technology in such a way that the plastic pipe retains its basic polymer properties at the turning point from pipe to flange face. The fittings are anyway injection molded (or Rotomoulded in some cases) using plastic resins, and are always without any weld joint.

The length of flanged pipe is generally restricted to a maximum of 3000 mm to take in to account the differential thermal expansion. The flaring is carried out in the pre-expanded plastic pipe under controlled conditions; so that at room temperature the plastic pipe exist in a slightly stretched condition. For its own atmospheric as well as internal protection, added safety and longer life the flanged steel pipes and fittings are hot dip galvanized after fabrication and before lining.

We at Jasma shall always be at assistance to select, recommend the appropriate lining material and to design the individual piping and equipment components to replace an existing line or for a new installation. On basis of Isometric layout drawings, details of piping arrangement and individual parts and sub assemblies’ drawings shall be submitted showing Face – Face dimensions and construction arrangements for approval before manufacture.

All the Pipe spools, Fittings and Equipment are cent percent tested for Spark Test and Hydro Pressure Test.