If you are involved in pallet network trunking, then you could be interested in this:
Strangely I was looking at one yesterday and wondered about how they strapped the pallets down. Mostly thinking about the top deck and various health and safety issues about climbing up there.
Surely if the curtain contained straps every 500 mm that would be adequate. Giving it a bit more thought, no it wouldn’t be good enough but there must be a simple solution.
Are the curtains on some deckers not load bearing?
Will_161:
Are the curtains on some deckers not load bearing?
hypothetical situation … the curtains are load bearing ,and the load shifts/becomes unstable. what happens when you loosen the curtain to unload ■■ not nit pickin ,just a thought when I read the above post 
I thought that too, I’ve never pulled deckers but I’m sure I heard somewhere that they can be load bearing.
Your situation applies to all curtain siders though doesn’t it?
2 of our deckers have got safety nets. They are on the runner where your internal straps would normally be with curtain buckles to secure them in place. Serves 2 purposes IMO. One is that they restrain the load and secondly you can undo the curtains and the freight is visible but still secure via the nets. It means if any pallets have collapsed en route, you can see it clearly and its not likely to fall out and land on someone.
We have some deckers in on hire that have nets and straps, the straps are fitted too far inboard and are a pig because they get caught on the top of the pallets.
A decker had its load come through the curtain coming down towards Elland from the M62 a few months back, pictures posted on here if I remember. It was a local company to us, and one of our gaffers was behind him and stopped to help{and also take photos, now pinned up at work about what could happen if you don’t use straps)
We have had pallets go over on the top decks before , used to get on the deck and see if could be handballed onto another pallet , if not the best thing to do was take pictures and open the curtain carefully and let the thing fall
Will_161:
Are the curtains on some deckers not load bearing?
That doesn’t help you when some FLT knob decides to put an engine block on a pallet on the top deck, and near the edge with a pallet of whisky boxes in front upstairs, and boxes of nuts and bolts behind. FFS. If it doesn’t go around the first roundabout out of fradley park of wherever, you’ll end up shooting it all down the M42 pulling up sharply in three lanes of stationary traffic so the tarmac gets as ■■■■■■ as a ■■■■. 
I’ve only been driving trucks for 15 years and from my experience of a curtain side’ed double deckers is that internal straps run the length of the trailer along the centre of the roof?
Are internal straps rated to any restraint capacity?
I suppose these internal straps then get lashed to a side rave! Not really a lashing point… (Yet again no rated capacity)
How can straps suspended from the roof physical restrain goods on the bottom deck?
chester:
How can straps suspended from the roof physical restrain goods on the bottom deck?
They can’t, it’s just for show so some H&S bod can tick a few boxes.
Any tension on them either bows the roof or twists the rails. The only thing that keeps most double deck loads secure is the hub monkeys ramming so much in nothing can move around it.
i used to work for palletways on a day trunk to lichfield with a double deck,we never used load restraints,but we were told to wear hard hats while in the warehouse at lichfield,when the hard hat rule came in i said what would be the point if a pallet came off the top deck and hit you on the head if you were not quick enough to move,a bit of plastic would not stop you getting seriously hurt or killed,but again its all to do with covering their own backsides,as regards health and safety,they could not care less if a driver was hurt or killed,to them you would just be a statistic,but then we drivers know that anyway