Indeed. 'Girder clamp' is what evolved from the old SK.
Gravlocks only have one bolt and have a thin wedge that slides over the steel.
If I'm incorrect then I would have learnt something new today...
pins / spigots
- Thread starter allan666
- Start date
Indeed. 'Girder clamp' is what evolved from the old SK.
Gravlocks only have one bolt and have a thin wedge that slides over the steel.
If I'm incorrect then I would have learnt something new today...
The only pin I ever liked was the SGB podger type. Remember once seeing a wrap round type, pin inserted in to tube and outer hinged gate tightened up. Remember it was a half inch fitting. Anyone got a picture.
philliosmaximus
Moderator
i remember them brandy they looked like a half sleeve half spigot thing
i always have a few spigots on board my lorry , you cant say its all down to bad planning all it takes sometimes is 6 inchs cut of a 21 and the sleeve is in the way of the lift , you are trying to judge where the lift will fall from 3 lifts down and your standards are staggered its almost impossible until you get there to see if a sleeve will be in the way.
celticbhoy
Moderator
think most of us are of the same opinion,very handy fitting,its there for us so why dont we use em guys.
i remember them brandy they looked like a half sleeve half spigot thing
i always have a few spigots on board my lorry , you cant say its all down to bad planning all it takes sometimes is 6 inchs cut of a 21 and the sleeve is in the way of the lift , you are trying to judge where the lift will fall from 3 lifts down and your standards are staggered its almost impossible until you get there to see if a sleeve will be in the way.
and how heavy are those bad boys
allan666
Well-known member
the only thing i was ever told not to do with them was top off if you werent going to be running the lift in to tie them together , incase the pin snaps , nice to see plenty replies
Ken Cain
Active member
Joint Pins / Spigots. - Allan66 has asked “What’s the law on these” so what does the law say about the use of pins or spigots. Its a very good question because we would all like to know about joint pins, I have heard so many conflicting stories about spigots being banned, with various reasons being given.
If spigots have been banned, then I want to see the evidence supporting the ban, and if spigots can only be used in certain situations I want to see the supporting evidence.
Someone should produce a simple easy to understand book which contains all of the information we need in respect of erecting and using scaffolds safely. I’ve gathered together some very important information regarding spigots and sleeve couplers as follows:
The Work at Height Regulations 2005 – Regulation 8(b) Schedule 3 - Part 1 – Subsection 4. Stability of working platforms – A working platform shall – (b) be so erected and used as to ensure that its components do not become accidentally displaced so as to endanger any person.
The Work at Height Regulations 2005 is an act of parliament and any breach of those regulations is considered to be a criminal offence.
Can spigot pins cause the joint to become accidentally displaced?
In answering this we will need to consider whether any of the joints in the scaffolding are in tension or compression so that we can decide on the type of fitting to be used.
Before deciding on the fitting we need to have a look at the British and European Standards regarding scaffolding and fittings.
The HSE have stated that “BS5973 is to be formally withdrawn by end of 2010 and the UK scaffolding industry should be fully conforming to the European Standard BS EN12811-1:2003 by the end of 2010”
OK then lets have a look at BS EN 12811-1:2003 and see what it says about couplers?
BS EN 12811-1:2003 – 10.2.4.2 Connecting devises – c) couplers complying with EN 74-1 –
So BS EN 12811-1:2003 tells us to use couplers to BS EN 74-1:2005 (E) which states:
4 Types and classes of couplers
4.1 Types of couplers
The types of couplers are listed in Table 1.
There is no mention in this table of joint pins or spigots in Table 1, so I assume we cannot use them?
7.1.7 Screw couplers shall be tightened with a torque of 50 Nm applied with a torque wrench conforming to 7.1.5
7.1.5 All test equipment shall have an accuracy ≤ 1 %. With exception, a torque wrench may have an accuracy of at least ± 5 %.
6 General Requirements
6.2.1 A coupler model of a defined type and class shall conform to all requirements specified in Table 8. (Table 8 specifies the types of couplings as: – Right angled couplers – Swivel couplers – Parallel couplers and Sleeve couplers)
There is no mention of Joint Pins or Spigots therefore one must assume that they cannot be used?
Is there any other document we could look at for advice?
NASC TG20:08
8 Standards
8.3 Joints
Joints in the standards of access scaffolds tied to a building may be made with either joint pins or sleeve couplers. Sleeve couplers of Class B are preferred. As these types of coupler have limited load capacity in tension, in scaffolds that are free standing or projecting above the level of a building or otherwise subject to forces which would produce tension in the standards, the standards should be joined in a manner capable of resisting the applied tension.
9 Ledgers
9.2 Joints
Joints in ledgers may be made with sleeve couplers or expanding joint pins. Where tension is likely to occur. Only class B sleeve couplers should be used. Joints in ledgers on the same lift and in adjacent lifts should not normally occur in the same bay. However, when guardrails are to remain permanently in place, the absence of a joint in the guardrail in any bay may be accepted as giving sufficient continuity to the scaffold to permit joints in the ledgers above and below it in the same bay. Where joints are necessary they should be positioned at a distance not greater than one third of the span between adjacent standards.
36.3 Couplers and fittings
Scaffold Couplers and other fittings should, when new, comply with the requirements of the relevant British Standard. If they have properties that do not comply with the relevant British Standard, then account should be taken of this in the design and construction of the scaffolding.
HSE Prosecutions
There have been several prohibitions issued where the scaffolder has failed to erect the scaffold in accordance with BS EN 12811-1:2003
An internal report by the Health and Safety Executive (2001) identified that 13% of scaffold collapses were due to faulty components being used.
If spigots have been banned, then I want to see the evidence supporting the ban, and if spigots can only be used in certain situations I want to see the supporting evidence.
Someone should produce a simple easy to understand book which contains all of the information we need in respect of erecting and using scaffolds safely. I’ve gathered together some very important information regarding spigots and sleeve couplers as follows:
The Work at Height Regulations 2005 – Regulation 8(b) Schedule 3 - Part 1 – Subsection 4. Stability of working platforms – A working platform shall – (b) be so erected and used as to ensure that its components do not become accidentally displaced so as to endanger any person.
The Work at Height Regulations 2005 is an act of parliament and any breach of those regulations is considered to be a criminal offence.
Can spigot pins cause the joint to become accidentally displaced?
In answering this we will need to consider whether any of the joints in the scaffolding are in tension or compression so that we can decide on the type of fitting to be used.
Before deciding on the fitting we need to have a look at the British and European Standards regarding scaffolding and fittings.
The HSE have stated that “BS5973 is to be formally withdrawn by end of 2010 and the UK scaffolding industry should be fully conforming to the European Standard BS EN12811-1:2003 by the end of 2010”
OK then lets have a look at BS EN 12811-1:2003 and see what it says about couplers?
BS EN 12811-1:2003 – 10.2.4.2 Connecting devises – c) couplers complying with EN 74-1 –
So BS EN 12811-1:2003 tells us to use couplers to BS EN 74-1:2005 (E) which states:
4 Types and classes of couplers
4.1 Types of couplers
The types of couplers are listed in Table 1.
There is no mention in this table of joint pins or spigots in Table 1, so I assume we cannot use them?
7.1.7 Screw couplers shall be tightened with a torque of 50 Nm applied with a torque wrench conforming to 7.1.5
7.1.5 All test equipment shall have an accuracy ≤ 1 %. With exception, a torque wrench may have an accuracy of at least ± 5 %.
6 General Requirements
6.2.1 A coupler model of a defined type and class shall conform to all requirements specified in Table 8. (Table 8 specifies the types of couplings as: – Right angled couplers – Swivel couplers – Parallel couplers and Sleeve couplers)
There is no mention of Joint Pins or Spigots therefore one must assume that they cannot be used?
Is there any other document we could look at for advice?
NASC TG20:08
8 Standards
8.3 Joints
Joints in the standards of access scaffolds tied to a building may be made with either joint pins or sleeve couplers. Sleeve couplers of Class B are preferred. As these types of coupler have limited load capacity in tension, in scaffolds that are free standing or projecting above the level of a building or otherwise subject to forces which would produce tension in the standards, the standards should be joined in a manner capable of resisting the applied tension.
9 Ledgers
9.2 Joints
Joints in ledgers may be made with sleeve couplers or expanding joint pins. Where tension is likely to occur. Only class B sleeve couplers should be used. Joints in ledgers on the same lift and in adjacent lifts should not normally occur in the same bay. However, when guardrails are to remain permanently in place, the absence of a joint in the guardrail in any bay may be accepted as giving sufficient continuity to the scaffold to permit joints in the ledgers above and below it in the same bay. Where joints are necessary they should be positioned at a distance not greater than one third of the span between adjacent standards.
36.3 Couplers and fittings
Scaffold Couplers and other fittings should, when new, comply with the requirements of the relevant British Standard. If they have properties that do not comply with the relevant British Standard, then account should be taken of this in the design and construction of the scaffolding.
HSE Prosecutions
There have been several prohibitions issued where the scaffolder has failed to erect the scaffold in accordance with BS EN 12811-1:2003
An internal report by the Health and Safety Executive (2001) identified that 13% of scaffold collapses were due to faulty components being used.
allan666
Well-known member
well put together that must of taken a while
Ken Cain
Active member
Pins / Spigots
Trouble is you have to go all around the houses to try and get the right answer, then when you think you are nearly there you discover that conflict exists between TG20 and BS EN 12811-1:2003. I put my money on BS EN 12811.
Trouble is you have to go all around the houses to try and get the right answer, then when you think you are nearly there you discover that conflict exists between TG20 and BS EN 12811-1:2003. I put my money on BS EN 12811.
celticbhoy
Moderator
ken thats the darn nearest weve had to an answer on anything mate thanks for that,fine post.but still confusion reigns lol.
Tony Mason
Well-known member
Good post, I belive the regs we should all be working to now are BS5975 with reference to BS,EN 12811.
Ken Cain
Active member
Important Information on SK and Gravelock Couplers
This is the link which will take you to a picture of the SK scaffold coupler: Google Image Result for http://www.kt-module.com/WebRoot/Store/Shops/gmb/4756/F8C7/9A7C/EC86/3890/41F3/657D/B44B/sc.jpg
There have been over the years a number of inconsistencies with the manufacture of the SK coupler. Although there is nothing wrong with the basic design of the coupler, minor inconsistances in the quality have caused difficulties when in use. The Gravelock Coupler manufactured by JW Raylor is of a better quality with minimal failures in the fitting.
This is the link which will take you to the photo of the Gravelock Girder coupler: Google Image Result for http://www.adsf.ae/img/products/formwork-falsework/61_image_sm.jpg
Both types of girder couplers must be used in pairs.
Both types are manufactured and tested to EN74-2:2005
The Gravelock is manufacture to Class B and has a slipping force of 10,0 kN and a pull apart force of 60 kN per pair of couplers.
The safe working load being 36 kN per pair of clamps. (approx 3.5 tonne)
Of course this is subject to the fitting being tightened to a torque of 50 Nm or 37 ft lbs force.
I hope this is of some help. Ken Cain
This is the link which will take you to a picture of the SK scaffold coupler: Google Image Result for http://www.kt-module.com/WebRoot/Store/Shops/gmb/4756/F8C7/9A7C/EC86/3890/41F3/657D/B44B/sc.jpg
There have been over the years a number of inconsistencies with the manufacture of the SK coupler. Although there is nothing wrong with the basic design of the coupler, minor inconsistances in the quality have caused difficulties when in use. The Gravelock Coupler manufactured by JW Raylor is of a better quality with minimal failures in the fitting.
This is the link which will take you to the photo of the Gravelock Girder coupler: Google Image Result for http://www.adsf.ae/img/products/formwork-falsework/61_image_sm.jpg
Both types of girder couplers must be used in pairs.
Both types are manufactured and tested to EN74-2:2005
The Gravelock is manufacture to Class B and has a slipping force of 10,0 kN and a pull apart force of 60 kN per pair of couplers.
The safe working load being 36 kN per pair of clamps. (approx 3.5 tonne)
Of course this is subject to the fitting being tightened to a torque of 50 Nm or 37 ft lbs force.
I hope this is of some help. Ken Cain
Ken Cain
Active member
Final Conclusion on Spigots
Joint Pins / Spigots – Final Conclusion -OK. We all want to know what the answer is to the Joint Pin / Spigot situation so that we can move on to the next query.
On Sunday I wrote “If spigots have been banned, then I want to see the evidence supporting the ban, and if spigots can only be used in certain situations I want to see the supporting evidence”
After presenting snippets of information from relevant Legislation, European and British Standards and TG20:08 we are probably not much wiser. There was no evidence suggesting that Join Pins or Spigots should be banned. It would be good to get some good sound advice and information on the joint pin which is unambiguous and easy to understand, not only that, it will help us feel more confident when we are discussing joint pins in the future.
What we don’t want is woolly ideas and made up stories that someone heard from someone else who said he knows about scaffolding.
OK then, here is the first question we want answered:
Can we use SPIGOTS?
YES WE CAN. Spigots can be used in certain situations as follows:
First we need to know the Safe Loadings of the fittings we are working with:
EXPANDING JOINT PINS – Slipping Force = 0.0kN. Shear Strength = 2.0kN. Ok that means then that the joint pin is of no help if the tube is under tension.
COLD PRESSED SLEEVE COUPLER (to BS EN 74-1:2005 Table 8) Slipping Force -Class A = 6,0 kN – Class B = 9,0 kN
To obtain the safe working loads of any BS EN 74 fitting in accordance with BS EN 12811-1:2003 – Table NC.1 – 10.3.2.1 divide the overall factor by 1,65.
Therefore the SLEEVE COUPLER – Class A after calculation for the factor of safety has a Safe Slipping Force of 3.63 kN – and Class B has a safe slippage of 5.45 kN – These forces are normally rounded up the nearest .05 kN to make the figures easier to use, therefore – Class A = 3.6 and Class B = 5.5
JOINTS IN STANDARDS
Joints in standards of independent scaffolds tied to a building, fully ledger braced including façade full height façade bracing may be made with either joint pins or sleeve couplers. Class B sleeve couplers are always preferred as they are stronger at resisting tension. In all free standing scaffolds, and independent tied scaffolds which project above the height of the building, or any scaffolds subject to forces which would produce tension in the standards, then the joints should be made with a minimum of a Class B sleeve coupler, or an approved method which is capable of resisting the applied tension. Joints in standards should be staggered with no more than three joints in the same bay, although its good practice to aim for a maximum of two joints diagonally opposite each other.
JOINTS IN LEDGERS
Ledgers should preferably be joined with sleeve couplers, but internal joint pins or spigots may be used if the joint is within 300 mm of a standard and there is no tension in the ledger.
Where tension is likely to occur only Class B sleeve couplers should be used. Joints in ledgers on the same lift and in adjacent lifts should not normally occur in the same bay. However if the guardrails are to remain permanently in place for the duration, the absence of a joint in the guardrail in any bay may be accepted as giving sufficient strength to the scaffold to allow joints in the ledgers above and below. Where joints do occur they should be positioned no more than 1/3rd into the span of the bay. When using sleeve couplers to support ledgers on working platforms, it is recommended that the bolts on the sleeve coupler are placed vertical i.e. so the wings of the coupling are horizontal.
In practice you may have to prove by calculation that there is no tension in the ledger being joined, it would be simpler to ensure that all joints in ledgers are made with class B sleeve couplers.
Class B sleeve couplers by Presco are selling at Approx 95p each.
Ken
Joint Pins / Spigots – Final Conclusion -OK. We all want to know what the answer is to the Joint Pin / Spigot situation so that we can move on to the next query.
On Sunday I wrote “If spigots have been banned, then I want to see the evidence supporting the ban, and if spigots can only be used in certain situations I want to see the supporting evidence”
After presenting snippets of information from relevant Legislation, European and British Standards and TG20:08 we are probably not much wiser. There was no evidence suggesting that Join Pins or Spigots should be banned. It would be good to get some good sound advice and information on the joint pin which is unambiguous and easy to understand, not only that, it will help us feel more confident when we are discussing joint pins in the future.
What we don’t want is woolly ideas and made up stories that someone heard from someone else who said he knows about scaffolding.
OK then, here is the first question we want answered:
Can we use SPIGOTS?
YES WE CAN. Spigots can be used in certain situations as follows:
First we need to know the Safe Loadings of the fittings we are working with:
EXPANDING JOINT PINS – Slipping Force = 0.0kN. Shear Strength = 2.0kN. Ok that means then that the joint pin is of no help if the tube is under tension.
COLD PRESSED SLEEVE COUPLER (to BS EN 74-1:2005 Table 8) Slipping Force -Class A = 6,0 kN – Class B = 9,0 kN
To obtain the safe working loads of any BS EN 74 fitting in accordance with BS EN 12811-1:2003 – Table NC.1 – 10.3.2.1 divide the overall factor by 1,65.
Therefore the SLEEVE COUPLER – Class A after calculation for the factor of safety has a Safe Slipping Force of 3.63 kN – and Class B has a safe slippage of 5.45 kN – These forces are normally rounded up the nearest .05 kN to make the figures easier to use, therefore – Class A = 3.6 and Class B = 5.5
JOINTS IN STANDARDS
Joints in standards of independent scaffolds tied to a building, fully ledger braced including façade full height façade bracing may be made with either joint pins or sleeve couplers. Class B sleeve couplers are always preferred as they are stronger at resisting tension. In all free standing scaffolds, and independent tied scaffolds which project above the height of the building, or any scaffolds subject to forces which would produce tension in the standards, then the joints should be made with a minimum of a Class B sleeve coupler, or an approved method which is capable of resisting the applied tension. Joints in standards should be staggered with no more than three joints in the same bay, although its good practice to aim for a maximum of two joints diagonally opposite each other.
JOINTS IN LEDGERS
Ledgers should preferably be joined with sleeve couplers, but internal joint pins or spigots may be used if the joint is within 300 mm of a standard and there is no tension in the ledger.
Where tension is likely to occur only Class B sleeve couplers should be used. Joints in ledgers on the same lift and in adjacent lifts should not normally occur in the same bay. However if the guardrails are to remain permanently in place for the duration, the absence of a joint in the guardrail in any bay may be accepted as giving sufficient strength to the scaffold to allow joints in the ledgers above and below. Where joints do occur they should be positioned no more than 1/3rd into the span of the bay. When using sleeve couplers to support ledgers on working platforms, it is recommended that the bolts on the sleeve coupler are placed vertical i.e. so the wings of the coupling are horizontal.
In practice you may have to prove by calculation that there is no tension in the ledger being joined, it would be simpler to ensure that all joints in ledgers are made with class B sleeve couplers.
Class B sleeve couplers by Presco are selling at Approx 95p each.
Ken
celticbhoy
Moderator
ken cain once again you are the man with the answers mate thanks.
Ken Cain
Active member
Thanks Joe
I quite enjoy sharing my knowledge with others, especially if its going to help them to work smarter and be safe. Ken
I quite enjoy sharing my knowledge with others, especially if its going to help them to work smarter and be safe. Ken
instructor
Well-known member
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Hi Ken as always first class.