Seat Belt Deceleration

[Eddie Brooks]

I am building a very old Lomax224 kit and need help in completing the Seat Belt deceleration to apply for IVA.

The seat belts are traditional 3 point retractable and secured to one existing chassis point and 3 points on a seat belt frame. With Lomax long our of manufacturing how do I get a declaration of suitability as required on the deceleration. Anyone any similar experience?

TIA

[Dcsinclair22]

Could you not go to a mot tester and get some kind of confirmation from them??

[Eddie Brooks]

Could try that. Makes you wonder what you are paying the IVA fee for

[nelmo]

Is anything like that required for IVA? They may check mounting points (although my guy didn't) but I've never heard of them testing the belts themselves. How would they - all they can really do is pull and check it locks, no?

[phaeton]

They will check the mountings to ensure they are adequate, they will also look at the bolt heads to make sure they are the correct grade, make sure you do not use any split washers that often come with seat belts kits. If they are inertia then they will check they lock & retract correctly, if they look old they may check the webbing to ensure there is no fraying.

[Eddie Brooks]

22 hours ago, phaeton said:

They will check the mountings to ensure they are adequate, they will also look at the bolt heads to make sure they are the correct grade, make sure you do not use any split washers that often come with seat belts kits. If they are inertia then they will check they lock & retract correctly, if they look old they may check the webbing to ensure there is no fraying.

 

[Eddie Brooks]

The unf bolts that came with the belts have no marking. The bolts I have used are M8 and marked 8.8. I believe that is ok.

[phaeton]

M8? are you sure they are normally 7/16UNF which is almost 12mm, M8 seems awfully small

[Sparepart]

I am wondering if you are checking your car against the IVA manual ?

In the section on seat belts, there is the following:-

Note 2: A suitable single bolt fixing of adequate strength would be, for example, a bolt of at least 11mm (7/16") diameter of grade 8.8 (the grade may not
be shown on a bolt produced for a seat belt anchorage). Other bolt fixings may be acceptable providing they are of equivalent strength. Two adjacent
seat belts may be secured by one bolt. In this case consideration must be given to the additional loads on the anchorage

Just in case you have not looked at the IVA manual, HERE is a link to the current version (today 2023-10-14) on gov website.

 

 

[Eddie Brooks]

Many thanks - I had looked but missed the need for 11mm or greater. Will need to swap for bigger diameter 

[Webstermick]

Hi also my car failed iva because seat belt anchor nuts where not fixed ie welded or captiveso nut would not turn 

[Eddie Brooks]

I know they are really keen that wherever possible self locking nuts are used - isn't that sufficient? Two bolts on mine go through a strengthened fibreglass bulkhead and I have put a spreader plate in behind it. If I weld nuts to it they won't be self locking ( the nylon inset will melt). Guess I will find out if they fail it

[phaeton]

4 hours ago, Webstermick said:

Hi also my car failed iva because seat belt anchor nuts where not fixed ie welded or captiveso nut would not turn 

That's an interesting one, I have IVA'd 3 cars in the last 3 years all with nylocks, none of them welded, all passed through a pieces of 6mm plate with a flat washer & nylock.

[phaeton]

1 hour ago, Eddie Brooks said:

I know they are really keen that wherever possible self locking nuts are used - isn't that sufficient? Two bolts on mine go through a strengthened fibreglass bulkhead and I have put a spreader plate in behind it. If I weld nuts to it they won't be self locking ( the nylon inset will melt). Guess I will find out if they fail it

Fibreglass only, nothing attached to the chassis? I'd have to read the section in the manual again but that just sounds wrong 

[Eddie Brooks]

Any guidance appreciated as this seems to be a minefield. Clip is bolted to chassis, shoulder is to tubular framework that is triangulated to chassis, reel and return go to plate at bottom of tubular framework (2mm). This plate is bolted to chassis but only with 7mm bolt.