First question to ask your self is how do I, get the pipe held firmly, what"s the maximum distance between fixings in the UK?? 1.5mtrs??, going to be a bit of a sod is it not having to chop holes every 1.5 mtrs in the inner skin just so that the pipes can be clipped to the wall, and making good again
Sounds a right daft idea to me, never even seen it done in 50 odd years in the trade
I think that this will be a catch all, for what you are proposing to do, a part cut and paste from the Statutory Instrument 1999 No. 1148, the way I read the SI its a No No, on what you are thinking of doing
The Water Supply (Water Fittings) Regulations 1999
Restriction on installation etc. of water fittings
3. - (1) No person shall-
(a) instal a water fitting to convey or receive water supplied by a water undertaker, or alter, disconnect or use such a water fitting; or
(b) cause or permit such a water fitting to be installed, altered, disconnected or used,
in contravention of the following provisions of this Part.
(2) No water fitting shall be installed, connected, arranged or used in such a manner that it causes or is likely to cause-
(i) waste, misuse, undue consumption or contamination of water supplied by a water undertaker; or
(ii) the erroneous measurement of water supplied by a water undertaker.
(3) No water fitting shall be installed, connected, arranged or used which by reason of being damaged, worn or otherwise faulty, causes or is likely to cause-
(i) waste, misuse, undue consumption or contamination of water supplied by a water undertaker; or
(ii) the erroneous measurement of water supplied by a water undertaker.
Requirements for water fittings etc.
4. - (1) Every water fitting shall-
(a) be of an appropriate quality and standard; and
(b) be suitable for the circumstances in which it is used.
(2) For the purposes of this regulation, a water fitting is of an appropriate quality or standard only if-
(a) it bears an appropriate CE marking in accordance with the Directive;
(b) it conforms to an appropriate harmonized standard or European technical approval;
(c) it conforms to an appropriate British Standard or some other national specification of an EEA State which provides an equivalent level of protection and performance; or
(d) it conforms to a specification approved by the regulator.
(3) Every water fitting shall comply with the requirements of Schedule 2 to these Regulations as it applies to that fitting.
(4) Where any requirement of Schedule 2 relates to a water system, every water fitting which forms part of that system shall be fitted or, as the case may be, altered or replaced so as to comply with that requirement.
(5) Every water fitting shall be installed, connected, altered, repaired or disconnected in a workmanlike manner.
(6) For the purposes of this regulation, a water fitting is installed, connected, altered, repaired or disconnected in a workmanlike manner only if the work is carried out so as to conform-
(a) to an appropriate British Standard, a European technical approval or some other national specification of an EEA State which provides an equivalent level of protection and performance;
(b) to a specification approved by the regulator; or
(c) to a method of installation approved by the water undertaker.