Oil & GasSealing, Insulation & Removable Valve Jackets

Customer Problem

OGDCL’s Dakhni plant was losing significant energy through its high-temperature process lines. The mild steel (MS) pipework itself was insulated, but the gate valves in those lines were not. Whenever high-temperature media was fed through the system, the valve bodies heated up and radiated that heat straight into the atmosphere — continuously, on every valve, for as long as the plant was running. The plant knew it was losing energy but had no practical way to insulate the valves, because any fixed lagging would have to be destroyed every time a valve needed inspection, operation or maintenance.

Technical Investigation

We worked directly with OGDCL’s equipment engineers rather than quoting from a distance. Together we walked the affected lines and confirmed the pattern: the pipe runs were lagged, but every valve was a bare, hot, exposed mass of steel sitting in the middle of an otherwise insulated line. Each one was effectively acting as a radiator. We also established the practical constraint that had caused the problem in the first place — these valves needed to stay accessible, so whatever we proposed had to be removable and refittable by plant staff, not a permanent enclosure.

Root Cause

The valves were not insulated because conventional lagging cannot be removed. This is the same reason valves go uninsulated in plants everywhere: the maintenance requirement and the insulation requirement appear to be in direct conflict, so insulation loses and the heat loss is quietly accepted as unavoidable. It is not unavoidable — it just needs a different kind of insulation.

Recommended Solution

We designed a custom removable insulation jacket for the valves — tailored to their dimensions, strapped rather than fixed, and built as a three-layer laminate, with each layer doing a specific job:

Inner layer — high-density Ceramic Fiber Wool. This is the layer that actually stops the heat. High density was specified deliberately: it holds its insulating performance at valve-body temperatures, where a lower-density or lower-grade material would compress, degrade and lose value.

Middle layer — PTFE Sheet. A barrier layer. PTFE is chemically inert and effectively non-absorbent, so oil, hydrocarbons and moisture from the plant environment cannot soak through into the ceramic fibre core. This matters more than it sounds: insulation that has absorbed oil or water stops insulating, and in a live oil and gas plant that contamination is a question of when, not if.

Outer layer — Silicone Coated Fiberglass Fabric. The skin. It has to survive weather, UV, oil splash, abrasion and being handled and re-strapped repeatedly by maintenance crews. Silicone-coated fibreglass takes all of that without cracking or perishing.

Installation Summary

The three layers were cut to the profile of each valve and sewn with heat-resistant aramid (Kevlar-type) thread. This detail is not cosmetic and it is the one most often got wrong: an insulation jacket is only as good as its seams, and ordinary polyester or cotton thread will degrade and burn through at valve-body temperatures — at which point the jacket comes apart precisely at the points holding it together. Aramid thread is what makes the assembly survive in service. The finished jackets were fitted to the valves with straps, so plant staff can remove a jacket in minutes for inspection or operation and refit it afterwards without damaging it or calling in a contractor.

Operational Result

With the jackets fitted, OGDCL reported a reduction of approximately 90% in the heat being lost at the jacketed valves — the customer’s own figure from their installation. That magnitude is consistent with what valve insulation does in principle: a bare hot valve is an efficient radiator, and enclosing it properly removes almost all of that loss. Just as importantly, the solution held up operationally, because it did not force the plant to choose between insulation and maintenance access — the jackets come off and go back on. Your own saving will depend on valve size, surface temperature and how many valves are currently bare; our Heat Loss Calculator will give you an estimate for your line.

Products Used

Related Resource Guides