RHS Limited
226-228 Holbrook Lane
It is difficult to generalise on all manufacturers of kit spiral staircases, although what can be said is that they are all continental and almost all do their own load testing etc. aimed at their own national standards but not specifically for the British Standard. The chances are that there will be something within the British Standard that will not be covered in the Continental equivalent and visa versa. That is not to say that either is wrong just different. Theoretically all us EU communities are attempting to eventually bat on the same wicket, but in the current state of the union that looks less like a priority.
So the questioner has his eye on a nice kit staircase and he knows that if someone claims that it complies with the British Standard then it will be acceptable under the Building Regulations. That is perfectly true but a very difficult claim to make with any adjustable spiral stair kit. The ability to adjust means that the end user can in all probability adjust say the tread rise outside of the British Standard maximum therefore it would not meet the standard. So, why not make the adjustments so that they can only remain within the standards. Yes a good solution, but whose standards, the Italians or the Brits! When you make a kit product to sell on the world markets it has to have built in compromises in an attempt to keep everybody happy as much as possible. If you were to go to a reputable bespoke spiral staircase manufacturer you should be able have a staircase made that will meet all the nuances of the British Standard but you will of course pay for the privilege. Reputable kit spiral stair companies should also be able to advise you on which spiral staircases you can use and how you can use them for specific project to meet the main conditions of the British Standard. It would however be a reckless company who boldly stated that it totally complies with everything in the British Standard, unless the manufacturer has had it independently tested and approved by a qualified body. The heavy costs of this procedure means that no continental manufacturer is ever likely to go through this process just for their British market. The only kit spiral stairs that I know of that have been specifically tested to BS 5395 part 2 are the Klan and Civik ranges. The report runs to 50 pages and even then they can only approve the specific sample submitted which means one specific diameter and one specific floor-to-floor height. The document does however lend credence to a Local Authority approving these particular spiral stair models providing that you check that your specific height and diameter can meet the requirements.
None of the above proves that any other make or model of spiral staircase is not suitable under the conditions of the British Standard, it is just difficult to prove it. As I understand it equivalent European standards should be acceptable in the UK but getting a document from the continental manufacturer that is in a language that is understandable and acceptable to your Building Control department may prove to be another matter.
As always I recommend that you talk to someone 'who knows' who can advise you on your specific project before you go too far. Judging by the number of kit spiral staircases that get approved each year by various Authorities all over the UK you may have less trouble than you think.
The spiral staircase Doctor.