Transcript condensation

Environmental Science
By John Bradley & Dr David Johnston – licensed under the Creative Commons Attribution – NonCommercial – Share Alike License
http://creativecommons.org/licenses/by-nc-sa/2.5/
ENVIRONMENTAL SCIENCE & SERVICES
LEVEL 1
Design tools and condensation
John Bradley
and
Dr David Johnston
Objectives and content
Objectives
Content
 Identify factors that influence heat loss in
buildings
 Determine fabric and ventilation heat loss
 Be aware of steady-state and dynamic
modelling tools
 Be aware of energy and environmental
assessment methods and standards

Heat loss from buildings

Energy and environmental
assessment and standards

Condensation
 Be familiar with psychrometric charts
 Understand the principles of condensation
 Identify sources of moisture within a
building
 Understand structural and dew point
temperature gradients
 Determine the purpose of a vapour barrier
Heat loss from buildings
 Factors affecting heat loss
 Calculation of heat loss
 Steady state methods
 Dynamic methods
Factors affecting heat loss
Total heat loss from buildings is made up of:
Fabric heat loss (Qf):
Conduction, convection and radiation exchanges
Ventilation heat loss (Qv): Exfiltration of indoor air through cracks, gaps and
openings
Qtotal = Qf +Qv
Important factors which affect heat loss are the:
 level of insulation contained within the building’s thermal envelope
 building’s location
 external surface area of the building
 temperature difference between the inside and the outside of the building
 air change rate of the building.
Calculation of heat loss
A number of methods have been devised which can calculate the rate at which heat
flows out of a building, and the quantity of heat that is lost within a given time.
These methods range in their levels of complexity and in the data input required by
the user, from:
simple U-value calculations,
rules-of-thumb
complex simulation
techniques
Note: All of these methods are approximations, and they can only provide a
simplified version of the complex energy interactions that take place within a
building.
The methods currently available can be split into two types:
 Steady-state (non-dynamic) methods
 Dynamic methods
Steady-state (non-dynamic) methods
These methods offer the simplest approach to modelling the thermal behaviour of a
building.
They assume that the temperatures inside and outside the building do not change
with time and the various flows of heat from the building occur at constant rates.
One of the simplest methods involves determining the building’s fabric and
ventilation heat losses.
Fabric heat loss (Qf) measured in Watts (W):
Qf = Σ (U.A.ΔT)
Where:
U
is the U-value of the building element
A
is the area of the building element
ΔT is the difference between the internal and external temperatures
Σ
is the sum of the individual values of (U.A.ΔT)
Steady-state (non-dynamic) methods
Ventilation heat loss (QV) measured in Watts (W):
Qv = cv.N.V.ΔT
3600
Where:
cv
is the volumetric specific heat capacity of air ( 1200J/m3K)
N
is the number of air changes of the room/building (ac/h)
V
is the volume of the room (m3)
ΔT
is the difference between the inside and the external temperature (°C).
The values for the specific heat capacity of air (cV) and the number of seconds
in an hour (3600) can be combined together to give the following simplified formula
for ventilation heat loss:
Qv = 0.33 N.V.ΔT
Steady-state (non-dynamic) methods
A number of other steady-state modelling tools are available. These include:
 Degree Day Method.
 LT4 Method.
 BREDEM (Building Research Establishment Domestic Energy Model).
In the UK, BREDEM is one of the most widely used non-dynamic approaches to
modelling the space heating requirement of dwellings.
The core of BREDEM consists of a two-zone model, which reflects the fact that
most dwellings are run with the living room temperature several degrees above that
of the rest of the house. Typical factors included in the BREDEM calculation are:
 Transmission and ventilation losses.
 Efficiency and responsiveness of the heating system.
 The user's choice of temperatures and heating periods.
 Solar gains.
 Internal and external temperatures.
Dynamic methods
These are more elaborate than steady state methods.
They essentially consist of a simplified, mathematical representation of a building's
thermal properties and processes.
The effects of time are included, allowing these models to more accurately model
the dynamic [ever-changing] heat interchanges that occur within the building, as well
as those that occur between the building and the external environment.
They have increased our ability to understand the complex interactions that occur
within buildings, such as those factors that involve thermal mass, solar gain and
internal heat gain.
A number of such dynamic modelling tools exist:
 Simplest - the Admittance Method
 More complex methods - computer based dynamic modelling tools such as:
ESP; SERI-RES; TRNSYS; and, HTB2. Extensively used to predict the
utilisation of solar energy in buildings.
Dynamic methods
Dynamic thermal models are essential for:





Assessing the importance of thermal mass to the performance of the building
Estimating peak temperatures
Estimating the energy benefits of passive solar energy
Estimating the energy benefits of internal free heat gains
Assessing the performance of any building in which free heat gains cover
most or all of the space heating load (e.g. superinsulated buildings)
 Assessing the importance of control systems and strategies (optimum start
controls, etc.)
However, there are a number of problems associated with dynamic thermal
models. These include:
 All practical implementations are 1 dimensional - buildings are 3 dimensional,
and the effects of corners etc. may be important.
 All implementations require careful approximation and exercise of judgement
 All formations make approximations regarding solar data and ventilation.
Actual versus predicted heat loss
However sophisticated the modeling of heat loss it will only be an approximation of
the actual heat lost in a building. A co-heating test can show the actual heat lost
from a building.
A co-heating test is a method of measuring the actual heat loss (both fabric and
background ventilation) in W/K attributable to an unoccupied dwelling. It involves
heating the inside of a dwelling electrically, using electric resistance point heaters, to
an elevated mean internal temperature (typically 25°C) over a specified period of
time, typically between 1 to 3 weeks. By measuring the amount of electrical energy
that is required to maintain the elevated mean internal temperature each day, the
daily heat input (in Watts) to the dwelling can be determined. The greater the
energy input required to maintain a particular temperature differential, the
greater the heat loss.
Actual versus predicted heat loss
Equipment required for a co-heating test
includes:
• Temperature sensors: to measure
internal temperature
• Fan heaters: to heat the dwelling.
• Circulation fans: to mix the internal air
within the dwelling.
• Thermostats: to regulate the heat
output from the fan heaters.
• kWh meters: to measure the electrical
energy consumption of fan heaters,
circulation fans and datalogger (if mains
powered). The kWh meters should have
a pulsed output that can be read by the
datalogger.
• Datalogger: to record the data obtained
from inside the dwelling.
Co-heating test equipment
[Source: Johnston, 2009]
Actual versus predicted heat loss
Co-heating tests carried out by Leeds Met suggest that the differences between
notional and actual heat loss can be significant:
For more details visit: http://www.leedsmet.ac.uk/as/cebe/projects/stamford/index.htm
The research at Stamford Brook suggests that one of the routes for the unexplained
heat loss is via the party wall cavity into the loft space. This source of heat loss is not
accounted for in calculating predicted heat loss using SAP.
Actual and predicted power requirement as a function of temperature differential
Actual energy required
Predicted energy
required
[Source: Wingfield, Miles-Shenton, Lowe and South, 2007]
More energy required to
maintain the
temperature differential
than predicted
Energy and environmental assessment and
standards
 Domestic buildings: assessment methods
 SAP
 Domestic buildings: standards
 Code for Sustainable Homes
 Non-domestic buildings: assessment methods
 Non-domestic buildings: standards
Domestic buildings: assessment methods
The assessment methods used for most of the UK’s energy standards for domestic
buildings are based on BREDEM, the Building Research Establishment
Domestic Energy Model. This predicts annual fuel use, fuel costs and CO2
emissions under a standard occupancy pattern (rating refers to the dwelling, not
the way it is used by a particular household). BREDEM is the basis of both the
National Home Energy Rating and the Standard Assessment Procedure
The National Home Energy Rating (NHER) is the leading domestic energy rating
scheme in the UK. The NHER rating of a dwelling is based on the estimated total
annual fuel use (for space heating, water heating, cooking, lighting and the use of
appliances), per square metre of floor space, under standard occupancy. It is
expressed on a scale of 0 (very inefficient) to 20 (very low carbon).
SAP is the Government's Standard Assessment Procedure for Energy Rating of
Dwellings. SAP 2005 is adopted by government as part of the UK national
methodology for calculation of the energy performance of buildings. It is used to
demonstrate compliance with Building Regulations for dwellings (Part L) and to
provide energy ratings for dwellings.
SAP
The Government’s Standard Assessment Procedure (SAP) for assessing the energy
performance of dwellings provides the following indicators:

The SAP rating is based on the energy costs associated with space heating,
water heating, ventilation and lighting, less cost savings from energy generation
technologies. It is adjusted for floor area so that it is independent of dwelling size
for a given built form. The SAP rating is expressed on a scale of 1 to 100, the
higher the number the lower the running costs.

The Environmental Impact rating is based on the annual CO2 emissions
associated with space heating, water heating, ventilation and lighting, less the
emissions saved by energy generation technologies. It is adjusted for floor area so
that it is independent of dwelling size for a given built form. The Environmental
Impact rating is expressed on a scale of 1 to 100, the higher the number the
better the standard.

The Dwelling CO2 Emission Rate is a similar indicator to the Environmental
Impact rating, used for compliance with Building Regulations. It is equal to the
annual CO2 emissions per unit floor area for space heating, water heating,
ventilation and lighting, less the emissions saved by energy generation
technologies, expressed in kg/m2/year.
The methodology is compliant with the Energy Performance of Buildings Directive.
Domestic buildings: standards
There are a number of standards by which domestic energy and environmental
performance can be measured:

Building Regulations AD Part L1

Energy Saving Trust Best Practice Energy Standards



Good Practice:
Best Practice:
Advanced Practice:
10% better than Part L1
25% improvement on Part L1
60% improvement on Part L1

AECB Silver and Gold energy standards

Passivhaus Standard: developed in Germany, supported by EU
Commission as pan-European standard for low carbon dwellings

EcoHomes Scheme: assesses buildings against a wide range
of environmental criteria and rates them as Pass, Good,
Very Good and Excellent. In part, superceded by:

The Code for Sustainable Homes: to be used in the design
and construction of new homes in England
Code for Sustainable Homes
Launched in December 2006 with the publication of ‘Code for Sustainable Homes: A
step change in sustainable home building practice”. This introduced a single national
standard to be used in the design and construction of new homes in England, based
on the BRE’s EcoHomes scheme.
The Code is a set of sustainable design principles covering performance in nine
areas:









Energy and CO2
Water
Materials
Surface water run-off
Waste
Pollution
Heath and well being
Management
Ecology
In each of these categories, performance targets are proposed in excess of the
minimum needed to satisfy Building Regulations, but are considered to be sound
best practice, technically feasible, and within the capability of the building industry to
supply.
The Code uses a rating system of one to six stars
Non-domestic buildings: assessment methods
The EU Energy Performance of Buildings Directive (EPBD) requires each member
state to create a methodology for the calculation of the energy performance of
buildings.
The Simplified Building Energy Model (SBEM) has been developed by BRE for
government as the default calculation for non-domestic buildings in the UK, and to
enable building regulations compliance checks and energy ratings to be carried out
on a consistent basis.
SBEM is a computer programme that provides an analysis of a building’s energy
consumption. It calculates monthly energy use and CO2 emissions of a building
given a description of the building geometry, construction, use and HVAC and
lighting design. These are then compared with those of a notional building.
Non-domestic buildings: standards
There are a number of standards by which non-domestic energy and environmental
performance can be measured:

Building Regulations AD L2: sets 5 criteria for new buildings to demonstrate
compliance and provides guidance on requirements that apply to existing buildings

BREEAM (Building Research Establishment Environmental Assessment
Method) is the main environmental labelling system in the UK for commercial
and industrial buildings. The basis of the scheme is the award of a certificate to
provide a 'label' for the environmental performance of a building.
BREEAM assesses the performance of buildings in 9 areas: Management, Health
and well-being, Energy, Transport, Water, Materials, Waste Land use and ecology,
Pollution. Credits are awarded in each area according to performance. A set of
weightings then enables the credits to be added together to produce a single overall
score. The building is then rated on a scale of Pass, Good, Very Good, Excellent
and Outstanding.
Summary
Condensation
 Humidity

Condensation in buildings

Structural temperature gradient
 Dew point temperature gradient

Interstitial condensation risk

Minimising condensation risk
Humidity
Moisture in the air, or humidity, influences the heat balance and comfort of the
human body, the durability of building materials and also causes condensation in
buildings
Air always contains some water vapour (wv) ie has humidity. The amount of water
that can be present in air is related to the ambient temperature. Warmer air can
contain more moisture than cooler air. When the upper limit of wv is reached, the air
is saturated.
The actual amount of wv in the air relative to the maximum saturation level is the
relative humidity (RH). The temperature at which air is fully saturated (ie at 100%
RH) is the dew point temperature. If the temperature falls below the dew point
temperature, the air cannot contain all the wv present and some wv will condense into
a liquid (ie condensation will occur).
Water vapour is a gas, suspended in air. It exerts a pressure which increases with
wv content and/or temperature. The pressure exerted by the molecules of wv
contained in the air is the vapour pressure. Pressure and temperature differentials
will cause warm, humid air to diffuse to colder areas, colder surfaces and permeate
colder structures, leading to cooling of the air and possible condensation.
Humidity: definitions
The amount of moisture in a given sample of air can be specified using a number of
different variables:
 Vapour pressure - The pressure exerted by the molecules of water vapour
contained within the air. Units: Pascals (Pa)
 Saturated vapour pressure - Vapour pressure which would be given by
saturated air at a specific temperature. (Units Pa)
 Dew point temperature - The temperature at which a sample of air with a given
moisture content becomes saturated. (Units: oC)
 Moisture content - The actual quantity of water vapour in a given sample of
air. (Units: g/kg of dry air)
 Relative humidity - Quantity of water contained within a given sample of air
expressed as a percentage of the maximum quantity of water which could be
contained within that air at that temperature. (Units: %RH at temp. in oC)
actual vapour pressure
RH (%) 
100
saturation vapour pressure
at given temp erature
CIBSE recommend that for most applications, the relative humidity should be
between 40% and 70% for human comfort.
Humidity: sources of
If no moisture is added to the internal air of a building, then condensation would
not be significant. However, in practice this is not the case.
The majority of the moisture within buildings comes from:
 Building occupants - sweating and breathing.
However, moisture also comes from:
 Cooking
 Clothes washing
 Clothes drying
 The use of un-flued heating appliances
 Industrial processes
Table A10.12 in the CIBSE Guide (CIBSE, 1999) gives estimates of the amount of
moisture likely to be produced from a variety of sources.
In addition, building materials will absorb moisture from the environment. This
moisture will then be released back into the atmosphere when the internal
conditions allow it.
Humidity: Psychrometric Chart
The variables used to specify the amount of water vapour in the air are interrelated.
The relationships can be shown graphically in a Psychrometric Chart. One version
of this type of chart is shown below:
[Source: Burberry, 1997]
Vertical axis: wv in air exerts a pressure - the vapour pressure (vp), so
air containing a large mass of wv has a higher vp than drier air. The
amount of water contained in air can be expressed as either vp (in kPa)
or the ratio of the mass of the wv to the mass of the air (in g/kg) – the
Moisture Content
Relative Humidity (RH) curves
These isoRH curves show the combinations of temperature and
moisture content that produce a given RH%
Saturation curve
Shows the combination of temperature and moisture
content at which the air is saturated ie RH of 100%. The
temperature at which saturation occurs is the Dew
Point Temperature. The curve is also known as the
Dew Point curve.
Examples:
1. What is the vapour pressure of air which is
at 20oC and has a relative humidity (RH) of
60% ? 
1400 Pa
2.
What is the vapour pressure of air which is
at 16oC and is saturated ?
1800 Pa


Example
If we have air at 20OC and 50% RH (point A) all the
moisture can be held in the air. If more
water vapour is introduced into this air and
the temperature of the air remains
constant, the RH of the air will increase. If
the RH is increased to 100% (saturation
point) point B, then any additional water vapour
that is introduced into this air will be
deposited as condensation. If on the
other hand, the amount of water vapour in
the air remains constant but the
temperature of the air falls, the RH of the
air will rise because the cooler air can
support less moisture. If the air is cooled
to around 10OC, the RH will rise to 100%
(saturation point) point C and any further
C
cooling will cause the water vapour
within the air to condense.
B
A
Condensation in buildings
There are two types of condensation:
 Surface - occurs on surfaces of the building envelope which are at or below the
dew point of the air immediately adjacent to them
 Interstitial - occurs within or between the layers of the building envelope when
the temperature of some part of the structure within the building envelope equals
or drops below the dew point temperature.
Surface condensation may occur:
 On the internal surface of external elements of a building.
 On cold pipes and cisterns within a building.
Condensation in buildings
Interstitial condensation may occur:
 On the surfaces of materials within a structure, particularly on the warm side of
relatively vapour resistant layers.
 Within the material when the dew point and structural temperatures coincide
throughout the material.
 On more than one surface in a structure. This is because moisture may
evaporate from one surface and re-condense on a colder one.
Interstitial condensation [Source: McMullan, 2007]
Condensation in buildings
The dampness caused by condensation can result in the following problems:
 Lead to mould growth
 Damage decorations and fittings
 Make insulating materials less effective
 Damage important structural materials, i.e. steelwork and timber
 In severe conditions it may even lead to structural failure
In addition, condensation can cause:
 Dimensional changes
 Reduction of thermal resistance
 Migration of salts and the liberation of chemicals
 Electrical failure
Structural temperature gradient
Heat will flow through the building fabric from an area of high temperature to one of
lower temperature.
For homogeneous materials:
 The temperature gradient through a construction will change uniformly
through each material within the construction.
 Temperature difference across a particular material is proportional to the
resistance of the material.
Therefore:
 Materials which have the highest thermal resistances will have the
steepest temperature gradients.
 Materials with the lowest thermal resistances will have the shallowest
temperature gradients.
High R
Inside
Low R
Outside
Inside
Outside
Structural temperature gradient
The boundary temperatures between the individual layers of the building fabric
can be determined from the thermal resistances which make up the U-value of
that element.
The boundary temperature at any point within a building element can be predicted
using the following equation:

R


R
 =

R
R
T
=
=
=
where
T
T
temperature difference across a particular layer (oC)
total temperature difference across the structure (oC)
resistance of that layer (m2K/W)
total resistance of the structure (m2K/W)
T
The calculation of the boundary temperatures within a building element enables
the temperature gradient throughout the element to be drawn on a scaled
diagram.
Structural temperature gradient: example
1. Find the inside surface temperature of an external wall which has a U-value of
1.8 W/m2K, when the internal temperature is 21OC and the external temperature
is -1OC.
Rsi = 0.123m2K/W
Rso = 0.055m2K/W
Solution:
Total temperature drop across the wall
  21   1  22 C
O
T
Total resistance of the wall
R 
T
1
1

 0.56m K/W
U 1.8
2
Using:


T

R
 0.123
0.123


  
 22  4.8 C
R
22 0.56
0.56
O
T
Therefore, temperature drop across internal surface layer
so inside surface temperature
= 4.8ºC
= 21 - 4.8 = 16.2 ºC
Dew point temperature gradient
A dew point temperature gradient can be plotted across a wall in a similar manner
to a structural temperature gradient.
Whereas thermal resistance is important to determine the temperature gradient,
vapour resistance is important in determining the dew point gradient.
The vapour resistance (RV) describes the ease with which a material will permit
the diffusion of water vapour.
R rL
V
where
RV =
rV =
L =
V
vapour resistance of the material (GNs/kg)
vapour resistivity of the material (GNs/kg m)
thickness of the material (m)
The total vapour resistance (RVT) of a multi-layered element is the sum of the
vapour resistances of all of the separate components.
R  R  R  ...
VT
V1
V2
Vapour resistivity
The vapour resistivity of a number of materials can be seen below.
Material
Aluminium foil
Plywood
Polythene film
Concrete
Wood
Plaster
Brickwork
Wood wool
Gloss paint
Mineral wool
Building paper
[Source: CIBSE, 1988]
Vapour resistivity (GN s/kg m)
>4000
150-520
125
30-200
50
35-50
25-40
15
8
5-6
5
Dew point temperature gradient
The vapour pressure drop across a building element can be determined in a
similar way to the temperature drop across a building element i.e.
R
P 
P
R
V
T
VT
where
P
R
P
R
V
T
VT
=
=
=
=
vapour pressure drop across a layer
vapour resistance of that layer
total vapour pressure drop across the structure
total vapour resistance of the structure
The vapour pressure changes can be used to produce a vapour pressure
gradient. However, it is more useful to obtain the dew point temperature at each
boundary layer from the psychrometric chart using the corresponding boundary
temperatures and vapour pressures.
If the structural and dew point temperature gradients are drawn on the same
scaled diagram and compared, the points at which the structural temperature falls
below the dew point temperature will indicate a risk of interstitial condensation
occurring.
Interstitial condensation risk analysis
An external wall is constructed of 10mm plasterboard, 22mm of expanded
polystyrene board (EPS) and 150mm dense concrete. The thermal resistances of
the components, in m2 K/W, are: internal surface resistance 0.123, plasterboard
0.06, EPS 0.75, concrete 0.105, and external surface resistance 0.055. The vapour
resistivities of the components, in MN s/g m, are: plasterboard 50, EPS 100, and
concrete 30. The inside air is at 20OC and 59% RH; the outside air is at 0OC and
saturated.
Use a scaled cross section diagram of the wall to plot the structural temperature
gradients and the dew point gradients, like this:
Interstitial condensation risk analysis
Step 1:
Use the thermal resistances to calculate the temperature drop across
each layer and the temperature at each boundary.
Total temperature drop(θT ) = 20 - 0 = 20OC
RT = 1.093
Layer
Inside air
Internal surface
Boundary
Plasterboard
Boundary
EPS
Boundary
Dense concrete
Boundary
External surface
Outside air
Thermal resistance
R (m2K/W)
0.123
0.06
0.75
0.105
0.055
RT = 1.093
Temperature drop
Δθ(ºC)
2.3
1.1
13.7
1.9
1.0
θT = 20


T

R
R
T
Boundary temperature
(ºC)
20
17.7
16.6
2.9
1.0
0.0
Interstitial condensation risk analysis
Step 2:
Use vapour resistances to calculate the vapour pressure drops across
each of the layers then, using the psychrometric chart, find the dew point
temperature at each boundary.
Inside vapour pressure
Outside vapour pressure
Total vapour pressure drop
Thickness
Layer
(m)
L
Internal surface
Boundary
Plasterboard
0.010
Boundary
EPS
0.025
Boundary
Dense concrete 0.150
Boundary
External surface
-
Vapour
resistivity
rv
50
100
30
-
= 1400 Pa
= 600 Pa
= 1400 - 600 = 800 Pa
Vapour
resistance
RV = L.rv
negligible
0.5
2.5
4.5
-
R
P 
P
R
VP drop
(Pa)
ΔP
53
267
480
-
negligible
RVT = 7.5
ΔP = 800
VP at
boundary (Pa)
1400
1347
1080
600
V
T
VT
Dew point at
boundary (ºC)
12
11.5
7.4
0
Interstitial condensation risk analysis
Step 3:
Plot the boundary temperatures on a scaled section of the wall and join
the points to produce a temperature gradient.
Step 4:
Plot the dew point temperatures on the scaled, section diagram and
produce a dew point gradient.
Scaled section diagram [Source: McMullan, 2007]
Minimising condensation risk: Vapour barriers
In walls constructed from permeable materials, water vapour can pass through the
structure, and evaporate from the outside surface.
However, if a wall has an impermeable outer face, evaporation will be prevented,
and the material may become saturated. This may lead to deterioration of the
building fabric and structure and mould growth.
The risk of interstitial condensation in building elements can be reduced if water
vapour is prevented from permeating through the construction.
Although no material is a perfect barrier to the transfer of water vapour some
materials do offer an acceptably high resistance. Such materials when used in this
way are called vapour barriers or a vapour check e.g., aluminium foil and
polythene sheeting - all of which have high vapour resistances.
Vapour barriers should be fitted to the warm side of the structure to minimise
vapour penetration.
Minimising condensation risk: Design
There are a number of ways in which good design can prevent the occurrence of
condensation within buildings. The factors that should be considered during the
design process are:
Factor
Means of reducing condensation risk
Moisture input
Moisture production from occupants cannot be controlled. However, the
moisture input from other sources should be either controlled by
extracting the moisture at source, or reduced by changing processes.
Ventilation
Increasing the ventilation rate will help to remove the moist air within the
building. Ventilation will be most effective if it is near the source of
moisture generation. Care should be taken to avoid excessive ventilation
as this will have an energy penalty.
Heating
Heating a building will raise the internal surface temperatures, keeping
them above the dew point temperature of the air inside the building. Care
must be taken to prevent excessive heating as this will not only incur an
energy penalty, but may also raise temperatures above comfort
conditions. If heating is intermittent, more continuous heating will raise
internal surface temperatures and structural temperatures, thus reducing
the condensation risk.
Insulation
Insulating the building envelope will help to raise the internal surface
temperatures of the building.
References
BSI (2005) BS 5250: Code of Practice for Control of Condensation in Dwellings. London: British Standards
Institution.
BURBERRY, P. (1997) Environmental Services 8th Edition. Mitchell’s Building Construction Series
CIBSE (1999) Volume A Design Data, 5th Edition. London: Chartered Institution of Building Services Engineers
CIBSE (2004) Guide to Energy Efficiency, London: Chartered Institution of Building Services Engineers
CIBSE (2006) Energy Assessment and Reporting Methodology, London: Chartered Institution of Building
Services Engineers
CIBSE (2007) , Environmental Design Guide A, London: Chartered Institution of Building Services Engineers
CIBSE (2007 a) Sustainability Guide, London: Chartered Institution of Building Services Engineers
DEFRA (2005) The Government’s Standard Assessment Procedure for Energy Rating of
Dwellings 2005 Edition, Watford: BRE
JOHNSTON, D. (2009) GHA monitoring programme – Phase 1. Report Number 1 – Draft Co-heating Testing
Proposal Leeds: Leeds Metropolitan University
McMULLAN, R. (2007) Environmental Science in Buildings. 6th Edition, London: MacMillan
RIBA (2007) Low Carbon Standards and Assessment Methods London: Royal Institute of British Architects
UK Green Building Council (2007) Report on Carbon Reductions in Non-Domestic Buildings London: DCLG
WINGFIELD, J. BELL, M. MILES-SHENTON, D. LOWE, B. and SOUTH, T. (2007) Interim Report Number 7 –
Co-heating tests and Investigation of party Wall Thermal Bypass. Partners in Innovation Project: CI 39/3/663.
Leeds: Leeds Metropolitan University.