Insulated Panels Expansion and Contraction!

[Grizzly]

Hi Guys!
The attached is one of a few photos I took of a Freezer Store Ceiling.
Note: The row of Threaded Suspension Rods with their Nuts and washers Loose.
These are the middle row of Three per panel.
Meaning the 2 outer sets of rods (to the left and right) which support the ends of 2 adjoining panels are tight.
All the way through the Roof the centre set of rods per panel.
Have clearance between the panel and the nuts and washers.

Should this be cause for concern?

I can only assume this is a good example of how much a insulated Panel can move when the panel has approx a 40c + difference between the outside (roof space @ say 20c) and the underside (Freezer roof @ -24c).

There are no damaged seals, all vapour seals are intact and no issues anywhere.

It's just strange to me to see this phenomenon!
Grizzly
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[al]

I always find a bit of bounce when walking on them, can't say i've seen that much gap though!

alec

[Magoo]

The panel jointers are riveted in place, so structurally fixed. The weakest point is the panel between, minute pressure changes from defrost and door openings will create a huge pressure differential on expansive panel area, only a few pa but will flex panels. Here the jointers are not riveted so can move and with a sealastic sealer will move constantly without leaking. Tighten hangers to reduce possibility of blowing a joint open and collapsing ceiling. It is all to do with pressure differentials not too much with expansion and contraction and temp differentials.

[Grizzly]

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Thanks for the input Guys!
Magoo thanks for your valued advise on and off the Forum.

I Have posted a couple more photos.
Please note that the rivets are not to hold the panels together.
But mearly a cap over the joint vapour seals.


Given the answers I have had.
I intend to pass these on to the guys running the site, advising them to speak to their Group consultant.

Building Fabric is not part of my remit.
I however to as a practise do walk the whole of the store, hence my query.

A shot vapour seal or Ice build up in pods etc.
Can dramatically affect the Refrigeration plant etc.

So I look for problems, don't always see them.

But if I look often enough I will!

Grizzly

[smpsmp45]

We had similar experience earlier. Infact there almost 15 ceiling panels were damaged.
The reason was the air cooling units were getting ON in one go. We changed the sequence of the units with start delay timers & the issue was resolved.

[joe-ice]

Maybe take a look at the room pressure relief valves , could be stuck , iced over.

[Grizzly]

Maybe take a look at the room pressure relief valves , could be stuck , iced over.
Thanks for the input.
It's nothing like that Joe.
Trust me this is a huge Store, more acres than square ft.
Anyway the bow is convex not concave.


As I have said this is a say what you see and let others act scenario!
Grizzly

[hookster]

Hi Grizzly you are correct with your analysis of the insulated panels. The phenomena you are witnessing is exaggerated in very long panels and although it is common to all insulated panels. The length of the panels makes it easier to observe. Thermal expansion of the panels is accommodated with thermal bow and thermal stresses in the panel. The composite sandwich of the panel does not elongate or contract with thermal changes but rather bends up and down (bow/stress). The panels are designed to accommodate this cyclic movement and tested to withstand a certain amount of cyclic movement. As you have observed the panel ends are held fast and the centre tie rods adjusted to allow cyclic movement up and down. These centre tie rods are there to prevent overload failure and retain roof integrity with excessive movement ie in a fire situation. Hope this helps

[Grizzly]

Hi Hookster.
Wise words, which go a long way to answering my dillema!
I will not put the photos in the post then!
;)
Keeping well I hope?
Grizzly