The Building Regulations Northern Ireland 2000 Part F

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The Building Regulations (Northern Ireland) 2000
Part F Technical Booklet F1 Conservation of Fuel
and Power in dwellings
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The Building Regulations (Northern Ireland) 2000
Part F

• DFP Technical Booklet F1 (2006) Section 3
• Existing dwellings

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Types of work covered by F1 Section 3 Existing
dwellings

• extensions
• creating a dwelling or part of a dwelling
  through material change of use
• provision or extension of a controlled service
• provision or extension of a controlled fitting
• replacement or renovation of a thermal element

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Historic buildings

• special considerations apply when compliance
  with the TB would unacceptably alter the
  character or appearance of the building
• aim should be to improve energy efficiency to
  the extent that is practicable
• Historic Buildings Energy Efficiency
• A Guide to Part F of the Northern Ireland
  Building Regulations 2006, EHSNI

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Definitions

• Controlled services
• Controlled fittings
• Thermal element

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Controlled fittings windows, roof windows,
roof-lights, doors

• A10 Giving of notices and deposit of plans
• application not required for replacement windows
  but replacement windows must meet the relevant
  requirements of the building regulations
• application needed for replacement external
  doors!

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Thermal element
a wall, floor or roof, but does not include
windows, doors, roof windows or roof-lights,
which separates a thermally conditioned space
from the external environment including the
ground and in the case of floors and walls,
another part of the building which is thermally
unconditioned (or which is conditioned to a
different temperature)

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Renovation/replacement of thermal element
Where a thermal element is renovated or
replaced such work shall be carried out as is
necessary to ensure that the whole thermal
element complies with the requirements of Part
F Renovation in relation to a thermal element
means the provision of a new layer in the thermal
element or the replacement of an existing layer
but does not include thin decorative surface
finishes

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Material change of Use
A9 Application to material change of use For the
purposes of these regulations a change in the
purposes for which or the circumstances in which
a building, or part of a building, is used shall
only be regarded as a material change of use if
after that change any one of the following cases
applies   Case I- the building is used as a
dwellinghouse, where previously it was not. Case
II- the building contains a flat or maisonette,
where previously it did not. Case III- the
building is used as   (a) a hotel or boarding
house, where previously it was not (b) an
institution, where previously it was not (c) a
public building, where previously it was not (d)
a shop, where previously it was not (e) an
office, where previously it was not or (f) a
store, where previously it was not. Case IV- the
building, by virtue of the change of use, is not
an exempted building where previously it
was. Where there is a material change of use to
the whole or part of a building the provisions
of the regulations set out in the Table to this
regulation shall apply.
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Building Regulation Part F1 Section 3 Existing
dwellings

• Extensions to Dwellings

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Building Regulation Part F1 Extension to
dwellings

• Three alternative approaches
• Standards Based Approach
• Calculated Trade-off Approach and
• Equivalent Carbon Target Approach

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Building Regulations Part F Technical Booklet
F1 Extension to dwellings

• Standards Based Approach
• (1st approach)

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Building Regulation Part FTechnical Booklet F1
Extension to dwellings

• Area of Openings
• Should NOT exceed the sum of
• 25 of the floor area of the extension plus
• Area of any window, roof windows, roof-light or
  doors which no longer exist as a result of the
  extension.

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• Controlled fittings
• Windows, roof windows, roof-lights, doors
• draught-proofed units with average area weighted
  performance not greater than

SAP Table 6e gives values for different window
configurations that may be used in absence of
test data or calculated values.
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• Provision of thermal elements
• New or Replacement walls, floors, and roofs
• as part of extension U-values

Max. U-value New thermal elements
Max. U-value Replacement thermal elements
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• Continuity to limit thermal
• bridging and air leakage
• Similar to new build
• The building fabric must be constructed
• in accordance with Accredited construction
  details,
• or, in accordance with BRE IP 1/06
• The builder must demonstrate that an appropriate
  system of site inspection is in place
• Copy of report must be given to District Council

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• Renovation of a thermal element
• 25 rule
• Where more than 25 of the surface area of a
  thermal element is being replaced, the WHOLE of
  that element must be upgrade to the improved
  U-value given in column (b) of Table 3.3
• Examples include
• Re-plastering external wall
• Re-slating roof
• Re-skimming a ceiling
• 15 year simple payback rule
• Applicant to prove that the upgrading is not
  technically or functionally feasible. The result
  will be a compromise upgrade which has a simple
  payback period of 15years.(See Appendix C)

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• Retained thermal element
• Existing thermal element becomes part of
  dwelling as result of a material change of use of
  becomes part of the thermal envelope and U-value
  gt column (a) table 3.3 the element to be upgraded
  to that of column (b) table 3.3.
• 15 year rule
• Applicant to prove that the upgrading is not
  technically or functionally feasible. The result
  will be a compromise upgrade which has a simple
  payback period of 15years.(See Appendix B C)
• 5 rule
• Upgrading to the above standards reduces
• usable floor area by gt5, or where additional
  
• insulation would create floor level/
  structural/ condensation difficulties.

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• U-values for retained thermal elements
• Thermal element becomes part of dwelling as
  result of material change of use

Current U-value
U-value to be achieved
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Building Regulations Part F Technical Booklet
F1 Extension to dwellings

• Calculated Trade-off Approach
• (2nd approach)

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• Calculated Trade-off Approach
• Fabric Standards and Opening Areas
• Similar to Standards Based Approach
• However the fabric standards and the opening
  areas values may be varied provided that
• The area-weighted U-value of all the elements in
  the extension is no greater than that of a
  similar size and shape notional extension which
  complies with the Standards Based Approach.
• The area-weighted U-value of each element type in
  not greater than the value in Table 3.4 and
• The maximum U-value of an individual element or
  part of an individual element is not greater than
  the value in Table 3.4.

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• Calculated Trade-off Approach
• Table 3.4 Limiting U-value

Max U-value for individual or part of individual
element
Area weighted U-value for each element
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Building Regulations Part F Technical Booklet
F1 Extension to dwellings

• Equivalent
• Carbon Target Approach
• (3rd approach)

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• Equivalent Carbon Target Approach
• SAP used to demonstrate the calculated CO²
  emissions rate
• from dwelling and proposed extension is no
  greater than for
• dwelling with a notional extension of the same
  shape and
• size complying with the Standards Based Approach.
• SAP2005 appendix S RDSAP (Reduced Data SAP)
• Used to estimate the performance of elements of
  existing
• building where unknown.
• Values in Table 3.4 are used for the
  Area-weighted average
• U-value and Maximum U-value.
• Additional upgrades are proposed to existing
  dwelling to
• compensate for lower performance in the
  extension, upgrades
• must comply with the relevant sections in TBF1.

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The Building Regulations (Northern Ireland) 2000
Part F
TB F1 Section 3 Existing dwellings

• Conservatories and
• Highly glazed spaces

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• Conservatory extensions
• Non-exempt conservatory must have-
• effective thermal separation from the dwelling by
  walls, windows and doors that are insulated and
  draught-proofed to at least the same standard as
  the same elements in the existing dwelling
• (Glazed elements that comply with Table 3.1
  column (b) and Thermal elements that comply with
  Table 3.2 column (b).)
• Where a heating system is installed, the heating
  appliance comply with DHCG, and heating system in
  the conservatory to have
• independent on/off and temperature controls
  separate from those on the existing dwelling.

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• Highly glazed extensions
• Highly glazed extension thermally separated from
  dwelling may be treated as a conservatory-
• Effective thermal separation from the dwelling
• Glazed elements that comply with Table 3.1 column
  (b) and
• Thermal elements that comply with Table 3.2
  column (b).
• Where a heating system is installed, the heating
  appliance to comply with DHCG, and
• the heating system shall have independent on/off
  and temperature controls separate from those on
  the existing dwelling.

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• Highly glazed extensions
• Highly glazed extension not thermally separated
  from
• dwelling to be treated as a conventional
  extension.

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• Material Change of Use

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Material change of Use
A9 Application to material change of use For the
purposes of these regulations a change in the
purposes for which or the circumstances in which
a building, or part of a building, is used shall
only be regarded as a material change of use if
after that change any one of the following cases
applies   Case I- the building is used as a
dwellinghouse, where previously it was not. Case
II- the building contains a flat or maisonette,
where previously it did not. Case III- the
building is used as   (a) a hotel or boarding
house, where previously it was not (b) an
institution, where previously it was not (c) a
public building, where previously it was not (d)
a shop, where previously it was not (e) an
office, where previously it was not or (f) a
store, where previously it was not. Case IV- the
building, by virtue of the change of use, is not
an exempted building where previously it
was. Where there is a material change of use to
the whole or part of a building the provisions
of the regulations set out in the Table to this
regulation shall apply.
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Material Change of Use
Regulation F2 a) i applies (Table to Regulation
A9)

• Reasonable provision shall be made for the
• conservation of fuel and power in any buildings
  by
• limiting heat gains and losses
• (i) through thermal elements and other parts
  of the building fabric and
• (ii) from pipes, ducts and storage vessels
• providing energy efficient fixed building
  services with effective controls and
• commissioning the energy efficient fixed building
  services prior to the completion of the building
  work

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Practical application ? ?

• Change of use to create new dwelling
• or apartments
• What would you expect to have to provide in
• terms of standards? equivalent to new build?
• Using some existing structure should you
• have to upgrade it?
• To what extent should you have to upgrade
• existing structure?
• To what standard should you have to build any
• new elements and provide in services and
  fittings?

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Material Change of Use to dwellings

• Two alternative approaches
• Standards Based Approach
• Equivalent Carbon Target Approach

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Material Change of Use to dwellings

• Standards Based Approach
• Similar to Standard Based Approach for extensions
• However,
• where any existing window or door that separates
  a conditioned space from an unconditioned space
  (or external air), has a U-value greater the 3.3
  W/(m2.K),
• it must be replaced to comply with values in
  Table 3.1

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Material Change of Use to dwellings

• Equivalent Carbon Target Approach
• SAP must be used to demonstrate that the
  calculated CO² emissions rate from the proposed
  dwelling is no greater than that for a notional
  dwelling.
• The U-value of any individual element must be no
  greater than the maximum U-value given in column
  (b) of Table 3.4.

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Material Change of Use to dwellings

• Material Change of Use
• An Energy Rating must be calculated for the
  dwelling AS BUILT and a NOTICE displayed similar
  to new build.
• Note regulation A9 Application to material
  change of use relating to Case 1 2 (C of U to
  dwelling flat or maisonette) states that only
  regulation F2 (a)(i) applies. (limiting heat
  gains and losses through thermal elements and
  other parts of the building fabric).
• However the new regulation A8B Application to a
  change to a buildings energy status must also
  be applied.
• Therefore TER and DER calculations are required
  for change of use applications.

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Controlled Services
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• Heating and Hot Water
• Efficiency similar to new build and
• Heating appliance to be replaced appliance must
  have an efficiency gt than 2 points lower than
  the appliance being replaced and
• Appliance to have controls that meet the minimum
  control requirements given in DHCG.
• Systems to be designed, installed and
  commissioned similar to new build
• Notice confirming the system has be properly
  commissioned to be provided to District Council
  and to the Building Owner similar to new build
• Notice to be signed by a suitably qualified
  person
• similar to new build

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• Internal and External
• Lighting
• Similar to new build
• The requirements apply-
• Solely to the extension
• or
• Material change of use whole dwelling
• or
• replacement lighting system which forms part of
  re-wiring works.

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• Operating and Maintenance
• Instructions
• Similar to new build
• Building owner must be given sufficient
  information to enable the dwelling to be operated
  and maintained in an energy efficient manner.
• The instructions to be directly related to the
  specific system(s) installed and readily
  understandable by the occupier e.g. How to make
  adjustments to timing and temperature control
  settings, what routine maintenance necessary to
  enable the systems to work at reasonable
  efficiency throughout their service life

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• Insulation of pipes, ducts and
• hot water storage vessels
• Generally similar to new build
• and in accordance with requirements given in
  DHCG.
• Replacing heating appliance or hot water storage
  vessel any pipes that a exposed as part of the
  works or are otherwise accessible should be
  insulated that meet the minimum requirements
  given in DHCG.

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• TB F1 Section 3
• Existing dwellings
• Workshop

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Example 2 Single storey extension to an
existing house

• The following plans show a proposed single storey
  extension to an existing house. The plans are to
  a scale of 1100.
• The extension measures 7.3m x 3.15m on plan and
  has a ceiling height of 2.3m.
• The extension has a flat roof and a solid ground
  floor.
• The five new windows each have an opening size of
  1.2m x 1.05m and it is planned to re-use the
  existing fully single glazed front door, which
  has an opening size of 2.1m x 0.9m.
• The existing front door, which is to be re-used,
  has a U value of 4.8W/m2K.
• It is proposed that the roof will have a U value
  of 0.19W/m2K and that wall will have a U value of
  0.28W/m2K.
• The windows are to be PVC-U double-glazed, argon
  filled low-E, soft coat, 16mm gap with a U value
  of 1.7W/m2K. The pivot windows have a maximum
  opening angle of 25o
• It is intended that there will be four light
  fittings, each containing two lamps, in the
  habitable room and one extra light fitting, with
  one lamp, in the extended hall.

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Example 2 Single storey extension to an
existing house
Existing ground floor
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Proposed ground floor
Example 2 Single storey extension to an
existing house
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Q1. Determine reasonable U values for the thermal
elements of the extension

• Suggested answer
• Amendment of Part A (Interpretation and general)
• A2 (1) Under Substantive Requirements A
  thermal element is defined as
• In these Regulations Thermal element means a
  wall, floor or roof, but does not include
  windows, doors, roof windows or roof-lights,
  which separates a thermally conditioned space
  from-
• a. the external environment (including the
  ground) and
• b. in the case of floors and walls, another part
  of the building which is
• thermally unconditioned or, where this paragraph
  applies, conditioned to a different temperature

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• (This will include all parts of the element
  between the surface bounding the conditioned
  space and the external environment or other part
  of the building as the case may be)
• 6 (h) b. only applies to a building which is not
  a dwelling, where the other part of the building
  is used for a purpose which is not similar or
  identical to the purpose for which the
  conditioned space is used.
• Hence from Table 3.2 Section 3 F1
• Wall 0.30W/m2K
• Floor 0.22 W/m2K
• Flat roof 0.20 W/m2K

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Q2. Determine reasonable U values for the
controlled fittings

• Suggested answer
• From Table 3.1
• Windows U-value 1.8 W/m2K OR Window energy
  rating Band D or
• Centre-pane U-value 1.2 W/m2K
• Fully glazed door 2.2 W/m2K or
• centre-pane U-value 1.2W/m2K

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Q3. Is it reasonable to reuse the existing front
door in the proposal?

• Suggested answer
• No, the door has a U value of 4.8W/m2K and from
  Table 3.1 the limiting U value for doors is
  3.0W/m2K

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Q4. Is the area of windows and door reasonable?

• Suggested answer
• No
• Area of windows and doors (5 x 1.2 x 1.05)
  (2.1 x 0.9) 8.19m2
• (para 3.8 a(a) (b)) Reasonable area 0.25 x
  3.15 x 7.3 (2.1 x 0.9) 7.64m2
• In some cases different approaches may be adopted
  by agreement with the BCB in order to achieve a
  satisfactory level of day lighting. BS 8206 gives
  guidance on this.

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Q7. Do the U values of the thermal elements and
does the area of windows comply with recommended
values?

• Suggested answer
• No

Proposed area of windows and door
8.19m2 Reasonable area windows and door 7.64m2
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Q8. Determine, using the area weighted average U
value method, if the proposal is satisfactory
with respect to the opaque and glazed areas
assuming it is intended to use a 2.1m x 0.9m
front door with a U value of 1.8W/m2K and U value
of floor is 0.25W/m2K?

• Suggested answer
• Yes it is satisfactory
• Proposed building
• Area of roof 3.15 x 7.3 22.995m2
• Area of wall including opening (3.15 7.3
  3.15) x 2.3 13.6 x 2.3 31.28m2
• Area of opaque wall 31.28 6.3 (2.1 x 0.9)
  31.28 6.3 1.89 23.09m2

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• Notional building
• Area of roof 3.15 x 7.3 22.995m2
• Area of wall including opening (3.15 7.3
  3.15) x 2.3 13.6 x 2.3 31.28m2
• Area of opaque wall 31.28 5.75 (2.1 x 0.9)
  31.28 5.75 1.89 23.64m2
• Element Area U value A x U
• Roof 22.995 0.20 4.599
• Wall 23.64 0.30 7.092
• Floor 22.995 0.22 5.0589
• Windows 5.75 1.8 10.35
• Door 1.89 2.2 4.158
• Total 77.27 31.26
• Area weighted area U value 31.26/77.27
  0.40W/m2K
• Area weighted average for the proposal is no
  greater than that of a notional extension.

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• Notional Extension
• Element Area U value A x U
• Roof 22.995 0.20 4.599
• Wall 23.64 0.30 7.092
• Floor 22.995 0.22 5.0589
• Windows 5.75 1.8 10.35
• Door 1.89 2.2 4.158
• Total 77.27 31.26
• Area weighted area U value 31.26/77.27
  0.40W/m2K
• Proposed Extension
• Element Area U value A x U
• Roof 22.995 0.19 4.36905
• Wall 23.09 0.28 6.4652
• Floor 22.995 0.25
  5.7487
• Windows 6.3 1.7 10.71
• Door 1.89 1.8 3.402
• Total 77.27 30.70
• Area weighted area U value 30.70/77.27
  0.40W/m2K

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Q9. Is there an alternative to following the
detailed guidance in the Technical Booklet?

• Suggested answer
• Yes
• 3.28 Where even greater design flexibility is
  required, reasonable provision would be to use
  SAP 2005 to show that the calculated CO2 emission
  rate from the dwelling with its proposed
  extension is no greater than for the dwelling
  plus a notional extension built to the standards
  of paragraphs 3.6 to 3.9. In these cases the
  area-weighted average U-value of each element
  type should be no worse than the standards set
  out in column (a) of Table 3.4, and the U-value
  of any individual element should be no worse than
  the values in column (b) of Table 3.4. The data
  in SAP 2005 Appendix S can be used to estimate
  the performance of the elements of the existing
  building where these are unknown.

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• 3.29 If, as part of achieving the standard set
  out in paragraph 3.20, improvements are proposed
  to the existing dwelling, such improvements
  should be implemented to a standard that is no
  worse than set out in the relevant guidance
  contained in this Technical Document. The
  relevant standards for improving retained thermal
  elements are as set out in column (b) of Table
  3.2.
• Where it is proposed to upgrade, then the
  standards set out in this Technical Booklet are
  cost effective and should be implemented in full.
  It will be worthwhile implementing them even if
  the improvement is more than necessary to achieve
  compliance. In some cases therefore, the standard
  of the extended house may be better than that
  required by paragraph 3.20 alone. Paragraph 3.21
  ensures that no cost-effective improvement
  opportunities are traded away.

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Q10. How would you expect it to be demonstrated
that reasonable precautions had been taken in the
design to avoid thermal bridges and air leakage?

• Suggested answer
• 3.14 A suitable approach to showing the
  requirement has been achieved would be to submit
  a report signed by a suitably qualified person
  confirming that appropriate design details and
  building techniques have been specified, and that
  the work has been carried out in ways that can be
  expected to achieve reasonable conformity with
  the specifications. Reasonable provision would be
  to
• a. adopt design details such as those set out in
  the Accredited Details or
• A list of additional approved details may be
  provided in due course.
• b. to demonstrate that the specified details
  deliver an equivalent level of performance using
  the guidance in BRE IP 1/06.

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Q11. In relation to the extension, what would
constitute the minimum reasonable number of
energy efficient light fittings to be provided?

• Suggested answer
• Two
• 3.48 A way of showing compliance would be to
  provide lighting fittings (including lamp,
  control gear and an appropriate housing,
  reflector, shade or diffuser or other device for
  controlling the output light) that only take
  lamps having a luminous efficacy greater than 40
  lumens per circuit-Watt. Circuit-Watts means the
  power consumed in lighting circuits by lamps and
  their associated control gear and power factor
  correction equipment.
• Fluorescent and compact fluorescent lighting
  fittings would meet this standard. Lighting
  fittings for GLS tungsten lamps with bayonet cap
  or Edison screw bases, or tungsten halogen lamps
  would not.

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• 3.46 Reasonable provision would be to provide in
  the areas affected by the building work, fixed
  energy efficient light fittings that number not
  less than the greater of
• a. one per 25m2 of dwelling floor area (excluding
  garages) or part thereof or
• b. one per four fixed lighting fittings.
• This assessment should be based on the extension,
  the newly created dwelling or the area served by
  the lighting system as appropriate to the
  particular case.
• 3.46 A light fitting may contain one or more
  lamps.
• 3.47 Lighting fittings in less used areas like
  cupboards and other storage areas would not count
  towards the total. GIL 20 gives guidance on
  identifying suitable locations for energy
  efficient luminaires. In some cases, it may be
  more appropriate to install the energy efficient
  light fitting in a location that is not part of
  the building work, e.g. to replace the fitting on
  the landing when creating a new bedroom through a
  loft conversion.

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Q12. What would constitute reasonable provision
for rapid ventilation and background ventilation
for the proposal?

• Suggested answer
• For Rapid and background ventilation, follow the
  guidance in TB K Table 2.1.
• From Table 2.1
• For each habitable room with external walls,
  1/20th floor area for window or external door
• For background ventilation, 8,000mm2 minimum
  equivalent area

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Q13. If as part of the work the owner intended to
replace the existing gas boiler what would be a
reasonable efficiency for the new boiler?

• Suggested answer
• From Domestic Heating Compliance Guide
• Replacements not involving a fuel or energy
  switch the seasonal efficiency of the new
  equipment should be
• as defined for new systems (i.e.86) AND
• not worse than two percentage points lower than
  the seasonal efficiency of the controlled service
  being replaced . If the efficiency of the system
  or appliance to be replaced is not known,
  efficiency values may be taken from Table 4a or
  4b of SAP 2005
• Replacement involving fuel or energy switch
• The aim is to achieve performance no worse in
  carbon emission terms. If the new heating system
  or heat generating appliance uses a different
  fuel, the efficiency of the new service should be
  multiplied by the ratio of the CO2 emission
  factor of the fuel used in the service being
  replaced to that used in the new service. before
  making this check. The CO2 emission factors
  should be taken from Table 12 of SAP 2005 - (the
  relevant column in Table 12 of SAP (2005) is that
  titled Emissions kg CO2 per kWh)

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Q14. If, and this is not the case in this
proposal, that it was proposed that an old
oil-fired boiler with a seasonal efficiency of
72 is to be replaced by a dual solid fuel boiler
with a seasonal efficiency of 65. What would be
the equivalent seasonal efficiency of the dual
solid fuel boiler?

• Table12 from SAP 2005
• Suggested answer
• The equivalent seasonal efficiency of the dual
  solid fuel boiler expressed in terms on
  equivalent oil boiler would be
• 65 x (0.265 ? 0.187) 92.1,

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Q15. Instead of the conventional extension, the
householder decides instead to have a
conservatory.It is proposed to construct a
conservatory with a totally glazed roof, glazing
to 60 of the wall area with glazed external
doorWhat would be reasonable standards to
satisfy F1 ifa) the conservatory had a floor
area of 40m2 and is thermally separated from the
existing house?b) the conservatory had a floor
area of 40m2 and is not thermally separated from
the existing house?c) the conservatory had a
floor area of 20m2 and is thermally separated
from the existing house?d) the conservatory had
a floor area of 40m2 and is thermally separated
from the existing house but only 50 of the roof
is to be glazed?
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• Suggested answer
• Under F1, Section 1, (1.1) a conservatory is
  defined as

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• Q15
• a) Hence, assuming that thermal separation from
  the house satisfies the above then reasonable
  provision for the conservatory construction would
  be
• U values
• Glazing 2.0 W/m2/K
• Wall 0.35W/m2K
• Floor 0.25W/m2K
• Glazed door 2.2W/m2K
• Any heating system to have independent
  temperature and on/off controls and to be in
  accordance with the Domestic Heating Compliance
  Guide

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• 3.23 Where the extension is a conservatory that
  is not exempt by Regulation A5(1)7, then
  reasonable provision would be to provide

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• Q15
• b) As there is no thermal separation between the
  construction and the existing house then by
  definition this is not a conservatory and should
  be treated as an extension, so, amongst other
  things, the guidance on area of glazing for
  extensions should be considered.
• c) This proposal is exempt the Regulations as the
  area of the conservatory is less than 30m2 but to
  qualify as a conservatory the thermal separation
  between the conservatory and the existing house
  should follow the above guidance
• Conservatories built at ground level and with a
  floor area no greater than 30m2 are exempt from
  the Building Regulations (but have to satisfy the
  requirements of regulations such as Parts K and
  V).

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• Q15
• d) The proposal is not a conservatory as less
  than ¾ of its roof area made from translucent
  material. BUT
• 3.24 If a substantially glazed extension fails to
  qualify as a conservatory because it has less
  than the minimum qualifying amounts of
  translucent material, but otherwise satisfies
  paragraph 3.24, reasonable provision would be to
  demonstrate that the performance is no worse than
  a conservatory of the same size and shape.
• A way of doing so would be to show the
  area-weighted U-value of the elements in the
  proposed extension is no greater than that of a
  conservatory that complies with the standards set
  out in paragraph 3.24.

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Example 3 Conversion of an existing attached
garage into a habitable room The plans are to
a scale of 1100.The existing flat roof has a U
value of 0.93W/m2K.The existing rendered cavity
block wall has a U-value of 0.70W/m2K and is
unsuitable for cavity fill.The existing windows
are single glazed with a U value of 4.8W/m2K.
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Existing Ground Floor Plan
Example 3 Conversion of an existing garage into
a habitable room
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Proposed Ground Floor Plan
Example 3 Conversion of an existing garage into
a habitable room
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Q1. How would you treat the proposal for the
purposes of Part F1?

• Suggested answer
• This could be considered as a material change of
  use of part of a building
• 3.30 Material changes of use involving dwellings
  are defined in Regulation A2 Interpretation as
  follows
• For the purposes of Regulation A9 (Case I) and
  for the purposes of these Regulations, there is a
  material change of use where there is a change in
  the purposes for which or the circumstances in
  which a building is used, so that after that
  change
• a. the building is used as a dwelling, where
  previously it was not

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• 3.30 When carrying out a material change of use,
  the Reasonable provision would be
• to follow the guidance in paragraph 3.31-3.32.
• 3.33 In normal circumstances, reasonable
  provision would be
• a. Where controlled services or fittings are
  being provided or extended, to meet the standards
  set out in paragraphs 3.37 to 3.50 of TB F1 (same
  as new)

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• b. Where the work involves the provision of a
  thermal element, to meet the standards set out in
  paragraphs 3.12 to 3.17 of TB F1.
• For the purposes of Building Regulations,
  provision means both new and replacement
  elements. ( build as new)
• c. Where the work involves the renovation of
  thermal elements, to meet the guidance in
  paragraphs 3.18 and 3.19 of TB F1 (upgraded)
• d. Any thermal element that is being retained
  should be upgraded following the guidance given
  in paragraphs 3.20 to 3.22 of TB F1(upgraded if
  necessary)

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• e. Any existing window (including roof window or
  rooflight) or door which separates a conditioned
  space from an unconditioned space or the external
  environment and which has a U-value that is worse
  than 3.3W/m2K, should be replaced following the
  guidance in paragraphs 3.10 and 3.11 of TB F1
  (replaced by new)

81
Q2. As part of the conversion work is it
reasonable to improve the thermal performance of
the roof?

• Suggested answer
• Yes, the roof is part of the existing opaque
  fabric that becomes part of the thermal envelope
  of the building whereas previously it was not.
  It is therefore a retained thermal element.
• As the U value is greater than the threshold
  value given in Table 3.3 (column a) of 0.35W/m2K
  it would be reasonable to improve the thermal
  performance.

82
Q3. For the roof what would normally be a
reasonable improvement to the roof?

• Suggested answer
• From Table 3.3 (column b) improve the U value to
  achieve 0.25W/m2K

83
Q4. When would such an upgrade be unreasonable?

• Suggested answer
• When it is not technically, functionally or
  economically feasible.
• 3.12 Reasonable provision would be to upgrade
  those thermal elements whose U-value is worse
  than the threshold value in column (a) of Table
  3.3 to achieve the U-value given in column (b) of
  Table 3.3 provided this is technically,
  functionally and economically feasible.
• A reasonable test of economic feasibility is to
  achieve a simple payback of 15 years or less.
  Where the standard given in column (b) is not
  technically, functionally or economically
  feasible, then the element should be upgraded to
  the best standard that is technically and
  functionally feasible and delivers a simple
  payback period of 15 years or less.

84

• Appendix B Simple payback means the amount of
  time it will take to recover the initial
  investment through energy savings, and is
  calculated by dividing the marginal additional
  cost of implementing an energy efficiency measure
  by the value of the annual energy savings
  achieved by that measure taking no account of
  VAT.
• a. The marginal additional cost is the additional
  cost (materials and labour) of incorporating
  (e.g.) additional insulation, not the whole cost
  of the work.
• b. the cost of implementing the measure should be
  based on prices current at the date the proposals
  are made known to the Building Control and be
  confirmed in a report signed by a suitably
  qualified person.

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• c. the annual energy savings should be estimated
  using SAP 2005 or approved software.
• D. Energy prices below were current in 2005 and
  can be used when evaluating the value of the
  annual energy savings but designers may use
  prices current at application date
• i. Mains gas 1.63 p/kWh
• ii. Electricity 3.65 p/kWh
• iii. Heating oil 2.17 p/kWh
• iv. LPG 3.71 p/kWh
• This is a weighted combination at peak and off
  peak tariffs.

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Q5. Is it necessary to improve the thermal
performance of the existing cavity walls?

• Suggested answer
• No, as the U value is not greater than the
  threshold value in Table 3.3 of 0.7W/m2K.

87
Q6. It is intended to dry line the existing
walls. Would it be reasonable to require the
thermal performance of the external wall to be
improved as part of this work?

• Suggested answer
• Yes.
• 3.12 Where a thermal element is being renovated
  reasonable provision in most cases would be to
  achieve the standard set out in column (b) of
  Table 3.3. Where the works apply to less than 25
  of the surface area however reasonable provision
  could be to do nothing to improve energy
  performance.

88

• 3.18 Renovation in relation to a thermal element
  means the provision of a new layer in the thermal
  element or the replacement of an existing layer,
  but excludes decorative finishes, and renovate
  shall be construed accordingly.

89
Q7. What would normally be a reasonable standard
to achieve?

• Suggested answer
• From column (b) of Table 3.3 a U value of
  0.35W/m2K.

90
Q8. What constitutes reasonable?

• Suggested answer
• 3.19 If such an upgrade is not technically or
  functionally feasible or would not achieve a
  simple payback of 15 years or less, the element
  should be upgraded to the best standard that is
  technically and functionally feasible and which
  can be achieved within a simple payback of no
  greater than 15 years. Guidance on this approach
  is given in Appendix B Simple Payback of F1.

91

• Appendix B Work to thermal elements
• 1 Where the work involves the renovation of a
  thermal element, an opportunity exists for cost
  effective insulation improvements to be
  undertaken at marginal additional cost. This
  appendix provides guidance on the cost
  effectiveness of insulation measures when
  undertaking various types of work on a thermal
  element.

92

• 2 Appendix C sets out the circumstances and the
  level of performance that would be considered
  reasonable provision in ordinary circumstances.
  When dealing with existing dwellings some
  flexibility in the application of standards is
  necessary to ensure that the context of each
  scheme can be taken into account while securing,
  as far as possible, the reasonable improvement.
  The final column in Table C1 provides guidance on
  a number of specific issues that may need to be
  considered in determining an appropriate course
  of action. As part of this flexible approach, it
  will be necessary to take into account technical
  risk and practicality in relation to the dwelling
  under consideration and the possible impacts on
  any adjoining building. In general the proposed
  works should take account of

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• a. the other parts of Schedule 1 and
• b. the general guidance on technical risk
  relating to insulation improvements contained in
  BR 262 and
• c. if the existing building has historic value,
  the guidance produced by DOE Environment
  Heritage Service guide Historic Buildings and
  energy efficiency. A guide to Part F of the N.I.
  Building regulations.
• Where, it is not reasonable in the context of the
  scheme to achieve the performance set out in
  Table C1 the level of performance achieved should
  be as close to this as practically possible.

94

• 3 Table C1 incorporates, in outline form,
  examples of construction that would achieve the
  proposed performance, but designers are free to
  use any appropriate construction that satisfies
  the energy performance standard, so long as they
  do not compromise performance with respect to any
  other part of the regulations.

95
Q9. Suggest a cost effective measure to achieve
the improved thermal performance of the wall.

• Suggested answer
• From Paragraphs 3.18 and 3.19
• Dry-lining to inner face of wall insulation
  between studs fixed to wall to achieve target U
  value thickness dependent on insulation and
  stud material used.
• Insulated wall board fixed to internal wall
  surface to achieve the required U value
  thickness dependent on material used.

96

• Assess the impact on internal floor area. In
  general it would be reasonable to accept a
  reduction of no more than 5 of the area of a
  room. However the use of the room and the space
  requirements for movement and arrangements of
  fixtures, fittings and furniture should be
  assessed.
• In situations where acoustic attenuation issues
  are particularly important (e.g. where insulation
  is returned at party walls) a less demanding
  U-value may be more appropriate. In such cases,
  the U-value target may have to be increased to
  0.35 or above depending on the circumstances

97

• Assess condensation and other moisture risks
  and make appropriate provision in accordance with
  the requirements of TB C. This will usually
  require the provision of a vapour control and
  damp protection to components

98
Q10. Is the renovation of the wall building
work within the meaning of the building
regulations?

• Suggested answer
• Yes
• Regulation A10 Schedule 2 Part B .(1) Where a
  person, intending to carry out any building
  work, renovation or replacement of a thermal
  element, change a buildings energy status or
  make any material change of use
• such work shall be carried out as is necessary to
  ensure that the whole thermal element complies

99

• Regulation A2 Interpretation (1) In these
  Regulations building work means
• the erection or extension of a building, the
  structural alteration or alteration of a building
  (including work in connection with the making of
  a material change of use) or the provision of a
  service or fitting.
• And includes
• the provision or extension of a controlled
  service or fitting in or in connection with a
  building
• the material alteration of a building, or a
  controlled service or fitting,
• work required by regulation A9 (requirements
  relating to material change of use)

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• the insertion of insulating material into the
  cavity wall of a building
• work involving the underpinning of a building
• work required by regulation A10 (requirements
  relating to thermal elements)
• work required by regulation A10 (requirements
  relating to a change of energy status)
• work required by regulation A10 Part B (4)
  (consequential improvements to energy
  performance).

101
Q11. What guidance is available on avoiding
technical risks when applying thermal insulation?

• Suggested answer
• The inclusion of any particular energy efficiency
  measure should not involve excessive technical
  risk. BR 262 provides general guidance on
  avoiding risks in the application of thermal
  insulation.

102
Q12. Should the existing windows be replaced?

• Suggested answer
• 3.30 In normal circumstances, reasonable
  provision would be
• Any existing window (including roof window or
  rooflight) or door which separates a conditioned
  space from an unconditioned space or the external
  environment and which has a U-value that is worse
  than 3.3W/m2K, should be replaced following the
  guidance in paragraphs 3.35

103

• 3.31 Where windows, roof windows, rooflights or
  doors are to be provided, reasonable provision
  would be the provision of draught-proofed units
  whose area-weighted average performance is no
  worse than given in Table 3.1 Column (a) applies
  to fittings provided as part of constructing an
  extension, column (b) to replacement fittings or
  new fittings installed in the existing dwelling.

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• End of workshop
• Thank you for you participation

105
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