Safe Working Load

[lx999]

Hi,

 

does anybody have a rough idea of the safe working load for one of the v.old fashioned cast metal lantern brackets as seen in a village hall near you. You'll all have seen one, usually added in a desperate attempt to add a bit of FOH, most commonly with a filthy old 23N bolted to it. I think they're made of cast aluminium, and they have a pivot at the base if that helps.

 

The reason I'm asking, is that I visited a local school, and saw a new and imaginative use for one, and before I call in the health and safety police I'd like to check my facts.

 

many thanks

[Brian]

Since it's a) cast and b) old there is no way to know. I guess if you had a pile of them you could do a set of destruction tests on the batch and derive a figure but other than that...

[lx999]

Since it's a) cast and b) old there is no way to know. I guess if you had a pile of them you could do a set of destruction tests on the batch and derive a figure but other than that...

 

Very true, the temptation to take a hammer to them is very strong! I think it's pretty safe to assume a fixing that was a) designed to take at most two lanterns, and b) is probably at least 40 years old, is well over loaded with about a 35kg load on it.

 

But I was hoping some smartie pants would actually know!

[Tomo]

But I was hoping some smartie pants would actually know!

Nobody in the entire universe can tell you the SWL of any item whatsoever unless they have either inspected the item itself or are the manufacturer of the item.

 

When a person or organization applies a SWL, they are opening themselves up to possible litigation should the item fail.

 

They therefore need to be able to justify the SWL they applied in a court of law, by measurement, calculation and testing.

 

So posters on a forum cannot and will not state SWLs.

[lx999]

But I was hoping some smartie pants would actually know!

Nobody in the entire universe can tell you the SWL of any item whatsoever unless they have either inspected the item itself or are the manufacturer of the item.

 

When a person or organization applies a SWL, they are opening themselves up to possible litigation should the item fail.

 

They therefore need to be able to justify the SWL they applied in a court of law, by measurement, calculation and testing.

 

So posters on a forum cannot and will not state SWLs.

 

UR Frank Wood and I claim my £5.00 : )

 

Correct me if I'm wrong, but don't manufacturers offer you a suggestion of what might be considered to be a SWL? Something along the lines of 'don't hang a MAC 600 from this screw eye'. I'm not completely new to this you know, I was hoping that someone might have come across the data in some dusty archive.

[pritch]

Surely asking this sort of thing is a bit like saying "Can someone tell me the top speed of my car? It's got four wheels and leather seats."

 

Even if someone did have the information lying around, without knowing exactly which bracket and from which manufacturer, any information you get will be a best guess, no more.

[paulears]

Francis - we now know you are "not completely new to it" - you're a new member, so you'll have to forgive us for not appreciating that you are not a total newbie. If you've been reading around the forum, you will spot easily that we are pretty intolerant of posts that appear to be asking "is this safe". So nobody ever says yes - as you realise. The trouble was in your original post, instead of giving facts, such as "There is a MAC500 hanging off an old cast bracket designed for a maximum load of around 6-7Kg. I think this is a ...... and I think I should ........" A post in this style lets people know you understand the problems, have enough knowledge to have arrived at your conclusion, and allows comment.

 

We still don't know what imaginative use you saw - so please don't get testy because we didn't know either.

 

We're all waiting now to find out what it was, and what you're about to do.

Paul

mods

[Andrew C]

Not really. These things were pretty standard, and I'd put money on the fixing to the wall being the weak point. The double-length ones would put a fair pull on the fixings if you were to put a couple of heavy lanterns on them though.

 

However, we are no nearer knowing what the rating of the rawlbolt / woodscrew in a hole packed with matchsticks is!

[Brian]

I was hoping that someone might have come across the data in some dusty archive.

**COUGH** **SPLUTTER**

Nope, nothing in the Strand 1975 catalogue in the way of data though the brackets do feature.

[lx999]

Francis - we now know you are "not completely new to it" - you're a new member, so you'll have to forgive us for not appreciating that you are not a total newbie. If you've been reading around the forum, you will spot easily that we are pretty intolerant of posts that appear to be asking "is this safe". So nobody ever says yes - as you realise. The trouble was in your original post, instead of giving facts, such as "There is a MAC500 hanging off an old cast bracket designed for a maximum load of around 6-7Kg. I think this is a ...... and I think I should ........" A post in this style lets people know you understand the problems, have enough knowledge to have arrived at your conclusion, and allows comment.

 

We still don't know what imaginative use you saw - so please don't get testy because we didn't know either.

 

We're all waiting now to find out what it was, and what you're about to do.

Paul

mods

 

Thanks for your comments, I've been a member of this forum since 2004, how long do you have to hang out before you graduate!

 

I'm not asking anyone to reassure me that something is safe, I thought I was asking if anyone knew what the manufacturers recommended loading for these devices was (I assume they were made by strand).

 

For ref: they are in use in a school hall, supporting one end of a 5m Steel Scaff LX bar (the other end being supported by a perfectly pukka stand off bracket), the bar is not entirely horizontal, and is rigged with a cantata (16:32), three prelude fresnels and some sort of generic hairy speaker box (large and heavy).

 

As I hinted, I'd like to be able to offer more than just my opinion when I speak to someone at the school. I assume because they have evidently been there for some time, and haven't fallen off the wall, the rawlbolts/plugs have been fitted correctly.

[paulears]

It's probably that I didn't explain that very well - as you've not posted much - the stats say 0 per day / 0.01% of total forum posts I shouldn't have used the word 'new'. I suppose we just don't know much about you - your ALD profile also makes you a little mysterious too. Not to worry - all seems ok now doesn't it - we know about the scaff and what's on it. I'd suspect that even if you mention it now, they're going to use history as their evidence of it being safe - and will ignore how long it will remain so! When my own theatre were having the steel wire ropes replaced, the engineers report stated the the correct termination method, then said "and not a reef knot" - for over 40 years that is how one of the bars was held up, and some grid pulleys were attached to the timber planks 'waggling' in free space. There's a lot more steel up there now, but like what you've described, the lash-ups had managed to work perfectly well. Difficult to explain this one!

[lx999]

It's probably that I didn't explain that very well - as you've not posted much - the stats say 0 per day / 0.01% of total forum posts I shouldn't have used the word 'new'. I suppose we just don't know much about you - your ALD profile also makes you a little mysterious too. Not to worry - all seems ok now doesn't it - we know about the scaff and what's on it. I'd suspect that even if you mention it now, they're going to use history as their evidence of it being safe - and will ignore how long it will remain so! When my own theatre were having the steel wire ropes replaced, the engineers report stated the the correct termination method, then said "and not a reef knot" - for over 40 years that is how one of the bars was held up, and some grid pulleys were attached to the timber planks 'waggling' in free space. There's a lot more steel up there now, but like what you've described, the lash-ups had managed to work perfectly well. Difficult to explain this one!

 

I'm not very verbose : )

 

but I agree with you about the history defence, doesn't cut much mustard when a bar falls off the wall though.

[adam2]

In view of the age of the equipment, I doubt that you will ever obtain a formal statement as to the SWL.

 

Ideally it should be replaced with somthing more modern that does have a SWL.

If financial reasons prevent this, it could perhaps be argued that the SWL is the weight of whatever lantern(s) it was originally designed for.

It could be argued that the use of modern lantern(s) of no greater weight than the orginals, has rendered the installation "no less safe" than was originally intended.

 

I doubt that a cast bracket has suffered wear or detioration, but it should still be carefully inspected in case, a greater concern, as others suggest would be the strength and suitability of whatever bolts, screws or other fastenings attach the bracket to the building structure.

 

There are firms that load test fixing points and issue certificates, but whether they would be willing to test something like this, I dont know.

[Brian]

... it could perhaps be argued that the SWL is the weight of whatever lantern(s) it was originally designed for.

It could be argued that the use of modern lantern(s) of no greater weight than the orginals, has rendered the installation "no less safe" than was originally intended.

So that's a Patt 123 then at 2.6kg.

[lx999]

... it could perhaps be argued that the SWL is the weight of whatever lantern(s) it was originally designed for.

It could be argued that the use of modern lantern(s) of no greater weight than the orginals, has rendered the installation "no less safe" than was originally intended.

So that's a Patt 123 then at 2.6kg.

 

Exactly, instead of a cantata (12kg), 5m steel scaff bar (c.25kg), three preludes (c.12kg) and a speaker (unknown, looks heavy!).