BBA Announcements/Policy Statements
11/01/12
Partial Fill Blown in and Injected
Cavity Wall Insulation - BBA Policy
BBA Agrément Certificates are currently
restricted for use with installations where there is no current
insulation material installed in the cavity. Recently the BBA has
been requested to assess the possibility of including installation
of Cavity Wall Insulation (CWI) where the cavity is already
partially filled with insulation and where CWI would be a top up to
this existing insulation.
Having considered the technical elements of
partial fill, and also taking into consideration on-going
discussions with the industry via NIA/CIGA, we wish to now publish
our policy relating to partially filled cavity walls.
If you wish to have your Agrément Certificate
amended to include partial fill situations, the following BBA
policy requirements shall be complied with:
As for all existing approvals, assessments
covered by this protocol will be restricted to two leaves of
conventional masonry construction and in compliance with the BBA
Height Restriction Waiver Policy.
It is assumed that the blowing machines and
nozzles, drill patterns and installed density will be as covered by
the existing approval.
Consideration of any variations to the above
will be subject to additional work and will require individual
assessment by the BBA on a case by case basis.
The applicant will define the material (and
BBA Certificate Number) that is to be used, the existing partial
fill material(s) to be covered and the minimum residual cavity
width for which they wish to be assessed.
Compatibility of materials
testing:
1.
Undertake desktop study for chemical compatibility
2.
Blow standard box which has been prepared as follows:
a.
Box material: Wood frame with wooden back and Perspex front. Front
to include strengthening to stop bending of Perspex panel
b. Vent
holes on sides and top
c.
Box dimensions 3m x 3m x 0.1m (residual cavity)
i. Depth of box adequate to achieve 100mm
residual cavity
d. Standard
drill pattern
e.
Attach insulation as normally to one face of box with standard
clips
f.
General requirements
(a) insulation, worst
case a very light thin EPS board
(b) quality of joint
butting, low
(c) residual cavity
depth, minimum proposed
(d) retaining discs,
minimal, e.g. one per long edge and those that grip the ties
relatively weakly
(e) alignment of board T
joints with a several blowing holes
3. Blow CWI
using standard system (machine drill pattern etc.).
Assessment of
compatibility:
1. Fill is
complete as per what would be expected
2. Underlying
partial fill insulation is not significantly damaged
3. Recovered
material density is within acceptable range
Wet wall testing:
Where the proposed blown in system has already
successfully undertaken a wet wall test at the minimum residual
cavity width proposed for the assessment (or lower) then no
additional wet wall test is required. However, if the proposed
residual cavity for filling is less than that for which the
original wet wall test was performed, then a separate test will be
required at this reduced width.
Assessors
The BBA will evaluate the Certificate holder’s
installer training procedures and published requirements for the
assessment of properties where blowing in insulation into an
existing partially filled cavity is to be considered, to ensure
that these are adequately rigorous and complete.
Certificates will include a statement
requiring all assessments of such properties to be carried out by a
BBA Approved Assessor.
Please note that compliance with the contents
of this letter does not mean that you discharge your statutory
duties as the scope of our requirements are limited to those
necessary for satisfaction of the BBA in terms of its certification
and assessment requirements.
BBA Position regarding
Eurocodes
04 November 2011
Since 2004 Approved Document A has quoted
both British Standard and European Normative “Eurocode” methods for
determining structural integrity but from 2013 reference to the BS
methods will be withdrawn. In Scotland, Technical Standard 1.1
requires that loadings shall be calculated in accordance with the
structural Eurocodes. However, 1.0.5 allows alternative approaches,
provided the designers / verifiers can satisfy themselves that the
proposed alternative is appropriate. The position is currently less
clear in Northern Ireland where Technical Booklet D refers to both
versions.
The BBA can demonstrate fitness for purpose
using any appropriate method, whether or not it is referenced in an
Approved Document, but to ensure maximum acceptance amongst users
and specifiers it has been decided to move away from British
Standard methods to Eurocodes as quickly as possible.
As a result, some changes will be required to
many BBA Certificates to cover the changeover from BS Codes of
Practice to Eurocodes.
The BBA is currently preparing detailed
processes covering the introduction of these changes, which is
expected to take several months. This will in due course result in
clients being advised of the situation and of any necessary updates
for their Certificates. If any Certificate holders would like to
discuss the likely implications for their Certificate(s) in advance
of the completion of this process, they should contact their BBA
Project Manager.
BBA launches Agrément Certificates for
hardware
The BBA has launched a new BBA Approval Scheme
for window and door hardware products. This has been launched to
improve the robustness of the approval process for hardware
products. As with all BBA Certificates the validity of these
hardware Certificates will be three years. Annual audit checks will
take place during the first and third year stages of audit testing.
The second year check will consist of a visit to the manufacturing
site.
Clients awarded a hardware Certificate will be
able to use the BBA logo with the appropriate certificate number in
their company literature and publicity material. The Certificate
will also be published on the BBA website as a downloadable
pdf.
The BBA will continue to offer Assessment
Reports for window and door hardware for clients that want them
but, due to the fact that many of the original test methods in
these reports have been superseded, a validity period of five years
has been set for new and existing Assessment Reports. After the
five year period the BBA will carry out a full reassessment to
check that the hardware is still manufactured as previously
assessed. Current Assessment Report holders with reports older than
five years will need to contact the BBA to obtain a quotation for a
reassessment should they wish for their report to remain valid.
Alternatively, they can now apply for a BBA Agrément Certificate
and gain the additional benefits that come with a rigorous and
thorough examination of the product, its manufacture and
installation.
Current window and door Agrément Certificate
holders that use hardware with existing Assessment Reports in their
products will be contacted by the BBA informing them about the
period of validity for Assessment Reports. They will be given
a period of grace of up to 12 months to change their hardware
should their existing suppliers not have a valid Assessment
Report.
For further information please contact
Luke Adams, Sector Manager at the BBA for windows, doors and
conservatories:
E-mail: ladams@bba.star.co.uk
Telephone: 01923 65300
Changes to height restriction waivers for BBA approved injected
cavity wall insulation
Currently the approval height for BBA certificated injected
cavity wall insulation products is limited to 12 or 25 metres. The
choice of the two height limits depends on the level of approval
sought by the client and the initial assessment carried out by the
BBA.
Historically, installers have been able to obtain a
site-specific waiver to go beyond the height limit stated in the
relevant Agrément Certificate following a satisfactory survey and
assessment by the BBA.
This policy has now changed and the BBA, with immediate effect,
will no longer issue site specific height waivers, with the
responsibility for individual assessments of the suitability of
particular sites above 12 metres being transferred to the System
Certificate holders.
The new height limit on all BBA Certificates for injected cavity
wall insulation units is set at 12 metres, or four storeys, of
typical domestic type construction.
Agrément Certificates currently referring to ‘height restriction
waivers issued by the BBA’ or having height limits above 12 metres
will be amended in line with this policy change and the new
responsibilities for installations above this height made
clear.
Should System Suppliers wish to maintain BBA certification for
installations over 12 metres, they must demonstrate to the
satisfaction of the BBA that they have the competence and
capability to manage such installations. Quality Plans can then be
amended to reflect these changes and the rigour of the Certificate
holders’ individual site assessments will be examined during
routine surveillance inspections.
Should an installer wish to install beyond 12 metres
authorisation should be requested from the System Supplier and not
the BBA.
The BBA will work with System Suppliers wishing to undertake
installations over 12 metres to help them implement the necessary
changes as efficiently and speedily as possible.
If you have any technical questions, please contact Dr Sean
Moriarty, Head of Approvals for Building Physics, at smoriarty@bba.star.co.uk
Testing the thermal conductivity of
EPS pre-foam beads for loose cavity wall insulation
application
Establishing complete confidence in the declared thermal
performance of insulation materials is of great importance to
potential specifiers or users. In order to develop further
understanding, and focusing on the thermal conductivity
measurements of expanded polystyrene loose beads, the BBA,
University of Salford and INEOS Styrenics Technology Breda have
performed a series of tests on the same EPS pre-foam using a Heat
Flow Meter and a Guarded Hot Plate.
As part of the process, a common methodology
was agreed by all three laboratories which covered the necessary
conditioning parameters and ways of determining the sample
density.
In addition to the requirements for EPS boards
in BS EN 13163:2008, loose bead samples are pre-conditioned by an
ageing process at 70oC for 48 hours before conditioning
at 23oC/50%RH to a stable state. The standard BS EN
12667: 2001 was used for the reporting of results and conducting
the measurement.
The results obtained when testing the same
samples were acceptably close. The sample preparation technique
requires the use of a 50 mm deep tray for pouring in the beads and
the determination of the “shaken-packed” density i.e. the density
when no more settling of the beads is observed.
In the light of these test results, the three
laboratories are now committed to using this method for determining
the thermal conductivity of EPS pre-foam beads. This is now BBA
policy for all future assessment and testing work and we will be
reviewing this policy when a product standard on the assessment of
this type of product comes into effect.
The BBA has recently contacted BBA Certificate
holders on the use of λ90/90 values. The approach for conducting
the statistical analysis as described in BS EN ISO 10456: 2007 will
be followed for establishing the declared value for beads. The
sample preparation will be as described above and the transition to
the use of λ90/90 values will be completed by the end of 2011 as
previously announced.
For more information please email testing@bba.star.co.uk or call
01923 665300.