In industrial plants, a large share of heat loss occurs not along straight pipe runs but at connection points such as valves and flanges. Because these points need frequent access during maintenance, they are often left uninsulated. Removable insulation jackets were developed to resolve exactly this trade off. This article looks at how a jacket application is planned and how the investment is evaluated.
Why Connection Points Matter?
The surface area of a single valve can be equivalent to several metres of pipe of the same diameter. As surface area grows, so does heat loss. Yet the valve is the component most often left out of the insulation scope.
The reason is practical. In a conventional application, reaching the valve means cutting the insulation, and restoring it to the same standard afterwards is rarely achievable. Over time these points are left open, and the plant ends up with a large number of uninsulated areas.
How a Jacket Is Built?
An insulation jacket consists of three layers. The inner face is made from a fabric suited to the operating temperature. The middle layer holds the insulation material, with thickness set according to line temperature. The outer face provides protection against external conditions and is chosen so that it can be cleaned in the field.
The layers are stitched together and closed with fasteners. When maintenance is required, the jacket is removed within minutes and refitted once the work is complete.
The Measurement Process
Jackets are not standard products; each one is made for a specific component. Measurement is therefore the most critical step in the process.
The survey records valve body dimensions, flange diameter, stem height and the size of any actuator. Connection orientation and the position of the line are also noted, since the opening direction of the jacket depends on access in the field.
Openings are left for instrument connections, drain lines and gauges. Missing these details at the survey stage results in a product that does not fit on site.
In plants with large numbers of components, giving each jacket a number and labelling it is worthwhile. Refitting each jacket to its own component then becomes straightforward.
Materials by Temperature
The inner layer is selected according to operating temperature. Glass fibre based fabrics are widely used in the medium temperature range, while ceramic based products come into play at higher temperatures.
Stone wool and ceramic wool are commonly used in the insulation layer. For jackets used on cold lines the design differs, since condensation control is required and a vapour barrier layer is added.
Which Components Are Suitable?
Jacket applications are not limited to valves. Flanged connections, pump bodies, heat exchanger covers, expansion joints, turbine components and exhaust lines can all be insulated this way.
The common factor is the need for access during maintenance. Where fixed insulation is used, every intervention means material loss, whereas a jacket is simply refitted.
Use Alongside Fixed Insulation
A jacket does not replace fixed insulation on straight runs. The two are planned to complement each other, with fixed insulation on pipe sections and jackets on components requiring access.
The junction between the two matters. Designing the jacket to overlap the fixed insulation prevents an exposed gap from forming at that point.
Evaluating the Investment
The return on a jacket application is calculated through heat loss. The calculation uses the surface area of the component, line temperature, ambient temperature, annual operating hours and the plant's unit energy cost.
On lines running at high temperature for most of the year, the payback period is shorter. On low temperature or intermittent lines it is longer. Ranking components by priority before applying jackets across a plant therefore gives a more efficient result.
Surface temperature measurements guide that ranking. A thermal camera survey makes it clear where the largest losses occur.
The Safety Aspect
Hot surfaces represent a contact risk as well as an energy loss. Insulating hot components located along walkways is one of the measures that reduces this risk.
In some plants, the decision to fit jackets is therefore taken on safety grounds independently of the energy calculation.
Installation and Follow Up
After fitting, the first check covers seating and closure points. Loose fasteners can cause the jacket to slip over time.
In the longer term, the key is tracking whether jackets are refitted after maintenance. A jacket left off cancels out the benefit of the application entirely. This follow up can be built into maintenance management processes.
If you would like Mod Endüstriyel Servisler to carry out a survey and assessment for the components at your plant, you can reach us through our contact page or review our insulation jacket services.
Frequently Asked Questions
How many times can an insulation jacket be removed and refitted?
This depends on operating conditions and the state of the fasteners. Jackets made to accurate measurements and refitted carefully can be used over a long period.
What information is needed for measurement?
Valve body dimensions, flange diameter, stem height, actuator size and the positions of instrument and drain connections are recorded.
How is the payback period calculated?
It is calculated from the component surface area, line temperature, ambient temperature, annual operating hours and unit energy cost. Higher temperatures and longer operating hours shorten the period.
Can jackets be used on cold lines?
Yes. For cold applications a vapour barrier layer is added to the design and condensation control is taken into account.