Fpd - Swivel Couplers

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TG6

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The pull apart force Fpd is supposed to be shown in table 5.15 in TG20 but isn't. I'm surprised that I don't have an amendment to correct the omission but I guess that no-one reads that part of the damned book.
I know that the pull apart force on a double is 12.2 kN (working load) so I can use clause 5.8.3 if I want to for doubles but I can't find any requirements for swivels.

Does anyone know what they are tested to or if there is a standard that gives this so that I can take advantage of a known figure or are they forbidden from taking pull apart loads?
 
TG6 said:
The pull apart force Fpd is supposed to be shown in table 5.15 in TG20 but isn't. I'm surprised that I don't have an amendment to correct the omission but I guess that no-one reads that part of the damned book.
I know that the pull apart force on a double is 12.2 kN (working load) so I can use clause 5.8.3 if I want to for doubles but I can't find any requirements for swivels.

Does anyone know what they are tested to or if there is a standard that gives this so that I can take advantage of a known figure or are they forbidden from taking pull apart loads?
Click to expand...

I am not sure table 5.15 has omitted any of the information it was intended to convey, it may however have omitted the information you were looking to find. Information which may well be found by reading on and following the reference to EN74?
 
Hi Alan

If you look at section 5.8.3, the formula includes a partial factor to check pull apart applied against pull apart capacity. Fpd is defined and reference made to finding it in table 5.15. As there is no value for Fpd for any couplers in table 5.15, you can't use the formula without going to some other document. EN12811-1 has a value for pull apart but it is a characteristic value and so is called Fpk. I don't have EN74 (no point having something that expensive that I only refer to once every ten years!) so can't check that but there is no mention of pull apart for swivels in 1139, merely an inferred requirement for the pin to be capable of carrying bending.
 
TG6 said:
Hi Alan

If you look at section 5.8.3, the formula includes a partial factor to check pull apart applied against pull apart capacity. Fpd is defined and reference made to finding it in table 5.15. As there is no value for Fpd for any couplers in table 5.15, you can't use the formula without going to some other document. EN12811-1 has a value for pull apart but it is a characteristic value and so is called Fpk. I don't have EN74 (no point having something that expensive that I only refer to once every ten years!) so can't check that but there is no mention of pull apart for swivels in 1139, merely an inferred requirement for the pin to be capable of carrying bending.
Click to expand...

Just stick to doubles then..............................if you do not use them then you dont have to worry:D
 
It's Saturday behave

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TG6 said:
Hi Alan

If you look at section 5.8.3, the formula includes a partial factor to check pull apart applied against pull apart capacity. Fpd is defined and reference made to finding it in table 5.15. As there is no value for Fpd for any couplers in table 5.15, you can't use the formula without going to some other document. EN12811-1 has a value for pull apart but it is a characteristic value and so is called Fpk. I don't have EN74 (no point having something that expensive that I only refer to once every ten years!) so can't check that but there is no mention of pull apart for swivels in 1139, merely an inferred requirement for the pin to be capable of carrying bending.
Click to expand...

Not sure why you find yourself needing to prove your fitting in this direction, what are you doing
PM me ref 74
Alan
 
Am I right in thinking you need someone to lay their ass on the line to give you the breaking point on the swivels rivet?

They come from China broken in the crate. Good luck Buddy lol

---------- Post added at 02:27 AM ---------- Previous post was at 02:15 AM ----------

This sh1t really annoys me. Give a scaff the job and draw it when you see it completed just like we did for years.

That's why you've all got bellies like Peachy 360 drivers.
 
Good point Swifty, do designers take into account loading on substandard chinese/indian fittings. Found quite a few pressed dubs and singles with gates out of shape out of square. crushed jaws.. Who passes these as fit for purpose, even pressed with en standards.:wondering:
 
frederik said:
Good point Swifty, do designers take into account loading on substandard chinese/indian fittings. Found quite a few pressed dubs and singles with gates out of shape out of square. crushed jaws.. Who passes these as fit for purpose, even pressed with en standards.:wondering:
Click to expand...

Something to be considered no doubt Frederik but............................
Not I feel within the remit of the Design Engineer, In most cases he/she is responsible the scaffold design not the quality of the gear sent to site by others.
 
SWIFTY said:
This sh1t really annoys me. Give a scaff the job and draw it when you see it completed just like we did for years.

That's why you've all got bellies like Peachy 360 drivers.
Click to expand...

I'm sorry, did I say something to upset you? Please explain what it was so that I don't repeat it.

I am all for scaffolders taking responsibility for putting it up without having to jump through the design, drawing, cat checks, approvals etc etc hoops that are put in our way nowadays but you only need to look at the Friday pictures and keep your eyes open while travelling around to realise that there is an increasing number of 'scaffolders' who don't have the experience or knowledge which is necessary to do this. No amount of design or drawing will fix that problem. As an industry we have to address the improvement of work standards on site instead of focussing on paperwork. Sadly, it's beyond me to do that.
 
Don't take it personally TG6. It was just a Saturday night rant. ;)
 
Had a look through EN 74, the only coupler that looks to be tested for pull-apart is the right angle coupler. You could try the manufacturer but if the test falls outside of the standard requirements, they may charge you for it.
 
See attached, as mentioned it is a strange requirement and as Nick has pointed out there is no apparent test for the Swivel,
See attached
 

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I'm assuming it's because swivels are primarily used for bracing that they felt that that type of test was redundant but who knows?
 
If the preasure was so great to pull apart,wouldnt tube bend first. just a thought,so shoot me down:wondering:
 
It may not be the Centre Pin that is the issue it may be the jaws restraining the bolt or indeed the hinge pin.
I have seen fittings with the jaws flattened out (they may have been oriental in origin) they may equally have been over tightened using an incorrectly set impact wrench but once flattened you have altered the design intention of the coupler which may also have a bearing on its ability to retain the bolt under adverse loading conditions.
 
Speaking of IW settings... I can't find the thread where the question was asked but: The range for impact wrench torque settings for scaffold couplers is 40 - 80 Nm, EN74 tests at 50 Nm tightening torque so that would be a safe bet.

I think Alan has it right with the pin (probably) not being the issue. Something else on the coupler will probably fail before the pin goes (Chinese stuff notwithstanding).
 
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