The difference between temporary and permanent structures?

What about tin roofs??? I know they are clipped down and even if the joints are spliced surely it still puts it on offer? I watched a street firm putting one in on Thursday and thinking Fook that!
 
It would depend it they've sealed the job bobby. If you havnt got the job sealed then your asking for trouble with the uplift on the scaffold.
 
How do you mean sealed den? I've only ever struck one never had the pleasure of putting one up lol is it overlapping the sheets?
 
Wether you use sheets or shrink wrap bob, if its sealed correctly from roof sheets to base lift then your getting rid of the uplift inside the structure. As for external loadings on the scaffold that should all be calculated by the designer in which case you then install the kentledge / ties to accomadate those loadings.

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Have a look at my photo folder at the temp roof and you'll see what i mean by sealed.
 
temp roofs i think should be sealed from roof to floor allowing access from any elevations as due to wind direction and i think their should be (if possible) a triangled deflection scaffold to divert wind from any direction,plenty of work through winter months for all builders,roofers and us
 
i think they should be sheeted from roof to floor(to aviod uplift) with access on all elevations due to different directional winds, to be closed as and when needed,i also think when possible a triangular buttress (sheeted) to divert winds off the main structure.Could be good for all during winter months for builders,roofers,etc.
 
scaffy 1980 said:
But that comes down to the installation of ties jagster, i've done countless jobs with mono and not one has come down.
Why.....cos it was tied correctly.
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Or is it because they have not yet faced the conditions required to dislodge them?

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scaffy 1980 said:
But surely that would come down to design al. Extra ties installed, a butress with extra kentledge on it.
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Scaffolds will only be designed to a typical set of criteria if these criteria are exceeded by "act of God" then they may well come down.

As you will see from watching a tornado on TV it cuts a path, building either side of the path may well remain untouched. This is the same with wind.

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gary wheaton said:
Drink wrap prob stop wind getting in side and causing any up lift..????
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Internal wind pressure may not always the same as uplift. Uplift can be caused by the wind passing over you roof structure similar to an airplane wing.

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scaffy 1980 said:
Looked at it and all i can find is its designed for wind loadings of 60km/h.
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37.5mph
 
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monoflex ties dont break under a certain pressure, every governor cringes when there are high winds, plastic on jobs is bad news i dont care how many ties you have, as the chap said would you put your house on it.
 
scaffy 1980 said:
But that comes down to the installation of ties jagster, i've done countless jobs with mono and not one has come down.
Why.....cos it was tied correctly.
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That's exactly right, if you tie in properly with the correct ties into a good substrate and test the ties, the monoflex will pop off before the scaffold goes over. Its no good bashing a couple of m16 anchors into some old brickwork with the end of a podger and expecting to be able to moor the Titanic to it
 
Monarflex isn't designed to come off the scaffold; all scaffolds, including the sheeted ones in TG20:08, are designed to withstand the full wind force in the same way as designing a permanent building. A properly designed scaffold will withstand any predictable wind load and factors of safety mean they will be withstand gust speeds well above any winds commonly seen (typically 120mph +). The best way to look at the Monarflex issue is what would happen if the wind is blowing the sheeting towards the scaffold, it cant snap the toggles then. Properly installed Monarflex will stay on the scaffold, Envirowrap even more so as its tensile strength is far higher than the wind pressure. Haki roof sheeting, tin sheets and ranch boards will also not come off a scaffold under wind loading if properly installed.
 
biffo0911 said:
Monarflex isn't designed to come off the scaffold; all scaffolds, including the sheeted ones in TG20:08, are designed to withstand the full wind force in the same way as designing a permanent building. A properly designed scaffold will withstand any predictable wind load and factors of safety mean they will be withstand gust speeds well above any winds commonly seen (typically 120mph +). The best way to look at the Monarflex issue is what would happen if the wind is blowing the sheeting towards the scaffold, it cant snap the toggles then. Properly installed Monarflex will stay on the scaffold, Envirowrap even more so as its tensile strength is far higher than the wind pressure. Haki roof sheeting, tin sheets and ranch boards will also not come off a scaffold under wind loading if properly installed.
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You might want to read this Biffo, its from the manufacturer of Monarflex. You're right to a certain degree, monarflex isn't designed to come off the scaffold, but neither are toe boards they just do in high wind. It is designed to blow off rather than take the structure down if installed to the design.

Recommended installation of Monarflex scaffold sheeting and the number of fixings required, when installing the sheeting.


All Monarflex scaffold sheeting should be installed in accordance with the current British standard code of practice for nets and sheets BS 8093, and the subsequent revisions in BS 7955, which states that a minimum of one scaffold sheeting fixing should be used per metre, in each direction.

All of the Monarflex scaffold sheeting range are designed as temporary protection products, the sheeting should be installed on the outside of the scaffolding, with the eyelets on Super T-Plus or reinforced bands on Scaffband or Stripe facing outward, this will allow the sheeting to detach in high winds, as per its design, alleviating the build up of pressure on the structure. The eyelets and bands have been positioned on the sheeting with a view that sheeting is installed horizontally. However the performance of the sheeting will not be impaired if installed vertically provided the one fixing per metre in each direction is achieved.

Monarflex Super T-plus products installed in conjunction with the Anchor & Strap fixings have been wind tunnel tested, whereby the sheeting and fixings withstood hurricane force winds up to 77mph, at which point the eyelets / Anchor & Straps gave way, as per its design. It is worth noting that the wind speed in the tunnel was steadily increased, subsequent research by the BRE has established that gusting conditions of approximately 40 mph plus can cause structural damage, gusts in this region will be sufficient to break the fixings and remove the sheeting.

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I remember working for Palmers in Luton. We had a site in Leighton Buzzard. A hurricane ripped through the site destroying the timber frame scaffold we had built, lifting it clear off the base plates and moving it a metre to the left, including the kentledge! forty yards away piles of insulation board ( shiny silver stuff) weren't even moved .The HSE visited, looked at the designs and basically said it was an act of God and nobody was to blame. Very strange the way the wind works.
 
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Thanks Russ,

I have that document too but as I stated the scaffold is designed for the full wind load whether or not the sheet detaches. There was a recent debate at the NASC technical committee regarding this and it was agreed that the manufacturer is wrong to state this on documentation. The Monarflex toggles will only snap if the sheeting is being pulled away from the scaffold which is only sometimes the case. A scaffold designer would never rely on the sheeting detaching from the scaffold therefore we design to British Standard wind codes in the same way as permanent buildings.
 
biffo0911 said:
Thanks Russ,

I have that document too but as I stated the scaffold is designed for the full wind load whether or not the sheet detaches. There was a recent debate at the NASC technical committee regarding this and it was agreed that the manufacturer is wrong to state this on documentation. The Monarflex toggles will only snap if the sheeting is being pulled away from the scaffold which is only sometimes the case. A scaffold designer would never rely on the sheeting detaching from the scaffold therefore we design to British Standard wind codes in the same way as permanent buildings.
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I see your point, but perhaps the NASC technical committee should share this information with the rest of us who actually erect scaffolding for a living as we are endlessly told to "Follow the manufacturers recommendations" and to be fair the British Research Establishment have tested this product.

Its simply not good enough agreeing that the manufacturer is wrong to state it on their documentation, has anybody told them they are wrong ? if so what are they going to do about it, or perhaps they think the NASC technical committee is wrong, its frustrating if you're the people at ground level with the job of installing.
 
Russ,

I totally agree that the manufacturer should be informed and I believe they will be soon. All sheeted scaffolds should be designed or constructed in accordance with a pre-designed arrangement such as those in TG20:08. As all of these are designed for the sheeting staying intact they are safe to construct and it makes no difference to the integrity of the scaffold what the manufacturer states.
 
biffo0911 said:
Russ,

I totally agree that the manufacturer should be informed and I believe they will be soon. All sheeted scaffolds should be designed or constructed in accordance with a pre-designed arrangement such as those in TG20:08. As all of these are designed for the sheeting staying intact they are safe to construct and it makes no difference to the integrity of the scaffold what the manufacturer states.
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Ok , Hypothetical question. I build a large scaffold, cover it in monarflex but fix the sheeting ties every .500mm in each direction instead of the manufacturers recommended interval of 1m, because after all, the NASC have agreed that the manufacturers recommendations aren't right. The scaffolds built to tg20:08, tied in according to sg4:11 and tested. A huge wind blows the scaffold down and kills an old dear and her dog ( Cuddles). HSE turn up and ask why the scaffold sheeting wasn't tied to the recommended 1m each way interval ? They argue that the sheeting , if tied to the specification, should have blown off and avoided the demise of the old dear and her dog (cuddles).After all, these people look at facts, the scaffold was built correctly, tested and tied so why would it fall down, there must be a reason. This must be the reason.

I now have two options to get me off the hook. I could use the old "Nasc technical committee agreed the Monarflex installation guide is rubbish, but haven't got round to telling anybody yet, so I ignored the manufacturers guidance " defence , but alas, they would probably counter with something like " but you didn't follow the correct sheet installation guide, making your sheeting twice as resistant to the wind ,thus killing the old dear and her dog (cuddles) the BRE have tested this stuff in wind tunnels and advise this tie interval, so there"

or the less appealing option of having to say, we built it properly, we tied it properly the only thing we deviated away from was the sheeting ties, we doubled them up. I'm guessing I'd go to jail and the NASC technical committee would be nowhere to be seen.

Obviously its a bit tongue in cheek, and I know you're in the design business, but you must see how it would look to the HSE ,after all if somebody dies they will pull out all of the stops to get a prosecution. Me mentioning that a guy on the forum said that the NASC technical committee have said that they think the monarflex tie intervals are wrong, therefore I ignored them , isn't going to work.
 
'A guy on the forum told me' sounds like a watertight defence to me. There's not a judge in the land could argue with such a sound argument. :D
 
I can hear the opening statement in the courtroom right now " Once upon a time, a guy on the scaffolders forum who I've never met before or know told me to throw away these instructions, the next day a big wind came and blew the scaffold down killing an old lady and her dog ( cuddles) " I'm guessing the ending statement wont read "And they all lived happily ever after"
 
Dangeruss you must be some sad gimp to go into detail with your specs and regs.as normal from experience your probably she/ite on the spanners
 
To be honest, who cares what you think...You probably think a band and plate is a dinner and dance.
 
Russ,

Again I agree and would install in accordance with the manufacturers instructions; I just wouldn't rely on the fact it is going to detach from the scaffold in high winds.
 
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