I got mine direct from the AMBSC, google it. I can't find anything in it which forbids girder stay, but you have to justify them being strong enough. There again mine isn't the latest issue.

As long as girder stays are adequately supported at the ends, and deep enough to take the bending load, I can't see anything intrinsically wrong with them

My engine has a steel boiler and is built to the AMBSC code with girder stays above the firebox.

I dont have a copy of the code for copper boilers but was told by my boiler inspector that girder stays can be used in a copper boiler provided that they meet all of the requirements in the code. And I believe that they have to be full height (from top of crown to inside of the outer wrapper) and the UK version allows partial height (someone in UK please advise if this is correct).    However, there is a preference to use rod type stays.

The AMBSC code for Australian boilers can be ordered from the Scale Model EXchange SMEX

Paul.

Edited By Paul Lousick on 29/12/2019 04:56:53

I work in Gauge 3, so our boilers are smaller than 5" ones, although most are still >3 BL.

The Orange book here in UK really just requires the Inspector to make sure the boiler is constructed in accordance to the given design and it assumes that this has normally been published by the Trade or in the Modelling Press. Where this isn't the case, the "designer" is required to produce the necessary calculations in support of their (new) boiiler design – or if an existing design has been altered or will operate at a higher working pressure.

In terms of the actual build quality, the following guidance is given:

c. Check that copper fireboxes with girder stay arrangements have adequate penetration of silver solder to all joints. d. Check that hollow stays (e.g. for blower) that are fitted by mechanical means have adequate strength and integrity of joints

That's about it I think.

Regards,

IanT