BS 644:2012 pdf free.Timber windows anddoorsets – Fully finishedfactory-assembled windowsand doorsets of varioustypes —Specification.
BS 644 The wood or wood-based components of a window or doorset shall either havesufficient natural durability, or be preservative treated.
NOTE 1 The sapwood of any species will require preservative treatment.
The natural durability of wood or wood-based components of a window ordoorset to be used without preservative treatment shall be at least durabilityclass 3 as defined in BS EN 350-2:1994.
NOTE 2 lf it is desired to use a species not listed in BS EN 350-2:1994, its durabilitycan be established in accordance with BS EN 350-1.
where the natural durability of the wood is class 4 or class 5 as defined inBS EN 350-2:1994, or where sapwood is present:
a)for preservatives for use in penetrating processes achieving the efficacy
criteria for use class 3 coated in BS EN 599-1:2009,Table 3b, option 2, thewood shall be preservative treated in accordance with BS 8417.For otherpreservatives listed in Bs 8417 as suitable for use class 3 coated, the woodshall be preservative treated in accordance with BS 8417;
b)for preservatives for use in superficial processes achieving the efficacy
criteria for use class 3 coated in Bs EN ‘599-1:2009,Table 3a, option 3, thewood shall be preservative treated so as to achieve a penetration class NP1(BS EN 351-1:2007) and a retention requirement of 1.5 times the criticalvalue.For field testing to BS EN 330, the preservative shall be applied usingthe manufacturer’s proposed method of application, and the referencepreservative shall be applied by double vacuum.
The preservative process shall be such as to provide a minimum desired servicelife of 30 years.
Any component or part of a component that is machined in a manner thatexposes untreated timber shall receive further treatment to ensure thecontinuity of the preservative envelope.
NOTE 3 The long-term performance of a window or doorset depends not only onthe maintenance of the preservative envelope but on the maintenance of thewindow or doorset as a whole (see Clause 9).
NOTE 4 Further information regarding the adjustment factors applied to the criticalvalue and the additional tests for efficacy can be found in BS EN 351-1:2007,5.3 andBs EN 599-1:2009,5.2.
Timberlaluminium composites lf aluminium extrusions are used as cladding or part of the window or doorsetframe, they shall be fabricated from designated alloys EN AW-6060 or EN AW-6063 in tempers T5 or T6 conforming to BS EN 755-2:2008 and
BS EN 755-9:2008 or BS EN 12020-1:2008 and BS EN 12020-2:2008.They shall befinished by anodizing conforming to BS 3987 or BS EN ISO 7599, with a liquidorganic coating conforming to Bs 4842, or by a powder coating conforming toBS 6496 or BS EN 12206-1.BS 644 pdf download.