HEAT TRANSFER
Fig 1 (right): A gate valve on a live plant. The cover is still on the asset, hanging open in two flaps, with the bonnet and gland flange bare. This is not a Fenix installation
Fig 2. (below): The plant as we found it on a turbine
outage. Right, what we drew off it. Every removable item numbered to a position, so anybody can ask for 119 in five years’ time and get 119
KEEPING TABS ON JACKETS T
Charlie Thompson, Fenix Industrial Group, discusses the concept of removable insulation, and the importance of keeping a record of what jackets are in use
hat is a gate valve on a live plant (see Figure 1). Somebody has taken the cover off to get at it, done what they went there to do and walked away. The straps are undone, the jacket
is hanging off the body in two flaps, and the bonnet and the gland flange are bare. It is not our work. The reason it is still like that is not laziness. It is that nobody on that site can replace it. Not will not. Cannot. There is no record anywhere of what that cover was. Close that cover up and you can lay your hand on it. It feels warm. That is it. No sizzle. Now take the cladding off a hot line and touch the metal. That will have the skin off your hand. Grey silicone sheds heat off its surface faster than polished metal does, which is exactly why it is comfortable to touch, and it is also why a cover that has gone missing makes no noise at all. Nothing burns anybody. Nothing trips. Nobody rings anybody. A removable jacket is the only insulation on a plant that can disappear without a single thing happening.
A jacket is cut and sewn to fit one valve, or one flange, or one strainer, once. It is not a length of material off a roll. It is a made item and it belongs to one position. So when it comes off for maintenance, or gets damaged, or walks, and nobody wrote down what it was, the site has two choices. Run bare. Or send somebody back out to measure that whole station again from scratch and make the lot a second time.
What should have been a five minute reorder was never possible, because the information that makes it possible was never captured. Three years later the record everybody needs does not exist and never did.
“It might have to come out in two years”. That is the line I hear more than any other. We will be pricing a job, they point down a run and say they want that with a jacket, and that, and that, and when I ask why, that is the answer. They want removable covers because at some point somebody might need to get at the valve, and they do not fancy paying a contractor three or four hundred pounds to come back, take a box off properly, store it, seal underneath it and keep water out of the system while it is open. Six, seven, eight times out of ten that cover comes off in year two and never goes back on. Take a jacket off and it looks like nothing at all. It sits on the deck, it goes in the skip, and it never enters anybody’s head again.
Nobody knows what was inside it either. Even
where somebody does go back to replace one, they copy what they find, and what they find is often wrong. We price a lot of this work and the same thing
turns up over and over. The pipework alongside is insulated to 150mm because that is what the specification calls for. Open the cover on the valve next to it and there is 50mm in there. Sometimes a bit of needle felt. No calculation anywhere, no thickness stated, nothing to check it against.
People seem to think the grey cloth is doing the work on its own, that it is a barrier in its own right and whatever you put behind it will do. It is not. What goes inside that cover is the same material doing the same job at the same temperature as the lagging on the pipe running past it, and given what that surface does, it wants the same thickness as the pipework, not a third of it.
I say this on jobs and it costs me. We price to the thickness the pipework specification calls for, somebody else prices 50mm in a cover, and we go home. The record is the cheap part. We number them before they come off. Every removable item gets a position on a drawing and a number on the cover, so when one goes missing in five years’ time somebody can ring up and ask for 119 and get 119, without anybody going back to site with a tape measure (Figure 2). This is just a list. What jackets are on the plant, where each one goes, what is inside it, and who had it off last. It costs almost nothing at the time, and it is worthless if you ask for it at handover, because by then the last trade has gone home. Ask for it in the enquiry, and write it into the ITP you are already asking your contractor to produce. And where something only comes off once in two years, clad it. Pay for the box one time. It will last longer and it will do a better job. Somebody has to take it off and put it back when the day comes, and that is a day’s work, not a problem. On the day he is stood there taking that one off there will be a hundred other things off around that plant. Have him walk it and survey the lot while his ladders are out.
Fenix Industrial Group is an industrial insulation and trace heating contractor working in power generation, energy from waste, water and process.
enquiries@fenixindustrialgroup.co.uk, T: 01227 678223.
Fenix Industrial Group
fenixindustrialgroup.co.uk
8 PROCESS & CONTROL ENGINEERING | OCTOBER 2026
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40
