why are we here?. the world health organisation guidelines for indoor air quality: dampness and...
TRANSCRIPT
Why are we here?
The World Health Organisation
Guidelines for Indoor Air Quality: Dampness and Mould (2009)
ISLINGTON COUNCIL’S CONDENSATION PROTOCOL
What’s the problem?
O Dampness within dwellings is unpleasant and potentially damaging to the health of residents. If left unchecked, it is likely to lead to the deterioration of the fabric of the building
O It is, as a consequence, of major concern to tenants and leaseholders
What is the aim of the protocol?
O To develop a planned, informed and consistent approach to investigating and tackling problems of damp and condensation with the aim of ensuring that all council homes are ultimately free from damp
O To assist LBI staff to diagnose incidents of damp and condensation correctly, to determine the cause and to specify the most appropriate remedial course(s) of action
How does LBI intend to achieve this?
O Via the council’s 30 year Asset Management Strategy:
O More than £2M/year has been set aside to fund planned works which will tackle known problems of damp and condensation
O Approximately £10M/year has been set aside to upgrade the energy efficiency of council homes by way of better heating systems and improved insulation
How will the money be spent?
O Via a seven year Asset Management Plan, delivered through the major works and improvement programme
How is the AMP informed in respect of energy efficiency
and damp?
O Database information regarding the age and condition of heating systems
O Analysing reports of condensation, damp and properties with heating problems
O Current repair and maintenance spending patterns
How is the AMP informed? (II)
O The availability of external funding for energy efficiency works
O Problems with specific building construction types
O Residents’ feedback in respect of energy efficiency works already completed
O Residents’ priorities in respect of estate improvement works
The day to day reality ‘on site’
O Responding to reported problems – inspect the property
O The repair of building defects leading to dampness
O Education and support of tenantsO Consideration of major works
schemes
Issues which need to be addressed or reported
O Water penetration, leaking pipes or rising damp
O Obvious cold bridges leading to condensation and/or mould growth
Heating
O Radiators not working correctly O Radiators appear to be undersized O Some spaces have no radiatorO Boiler not working correctly
O In each case refer to M & E team or raise repair, as appropriate
Ventilation
O Are extract fans working correctly?O Are there any trickle vents?O Do the windows operate correctly?O Are airbricks blocked?
O In each case, give advice, raise repairs or report as appropriate
Issues where tenants may require assistance
O Central heating programmer not being used (TO explain/ demonstrate use)
O Radiators require bleeding (ditto)O Heating not being used effectively
(ditto)O Property is overcrowded (advise on
housing options)
Seasonal Health Interventions Network
O If behaviour seems to be the problem, the tenant is vulnerable and more assistance is required than the surveyor or housing officer can provide, refer to SHINE
Developing the bigger picture
O Following inspection of the property:
O Check the repairs records for the blockO Contact other tenants where condensation
has been reportedO Inspect at least two properties where
condensation has not been reportedO If condensation/mould is found in these
properties, refer to the High Value Repairs Panel
What is condensation?
O Air holds moisture in the form of water vapourO The amount of moisture in any given sample of
air expressed as a percentage of the maximum amount of moisture air at that temperature could hold as vapour is called the relative humidity
O Warm air can hold more moisture than cold airO When air is cooled, the relative humidity risesO The temperature at which RH reaches 100% (i.e.
the air is saturated) is called the dew pointO Any additional moisture or any further cooling
cannot be held as water vapour and is given up as liquid water - CONDENSATION
A
C
B
D
Moisture contentof air – g/kg
Dry bulb temperature -� C
Relative humidity %
The inspection
O Sources of dampness in buildings:
O Penetrating dampO Rising dampO Leaking pipesO Condensation
The ‘condensation factors’
O The production of moistureO VentilationO HeatingO The design and construction of the
building
The production of moisture
People: 1.2kg/person/day
Cooking: Electricity 2kg/day
Gas 3kg/day
Dishwashing: 0.4kg/day
Bathing/washing: 0.2kg/person/day
Washing clothes 0.5kg/day
Drying clothes indoors1.5kg/person/day
The production of moisture (II)
O BS5250:2011 Code of Practice for Control of Condensation in Buildings:
O ‘The first and most important step is to avoid generating moisture within the building as far as possible and to limit the spread of warm moist air from one room to another’
VentilationO BS5250:2011 makes the following
recommendation:
O ‘The most efficient and cost-effective way to remove excess moisture is by natural ventilation. This relies upon the buoyancy of warm internal air and the provision of carefully sited vents which encourage a steady flow of air through the building. Alternatively, excess moisture may be removed and condensation minimized by mechanical extraction, such as using an electrical fan controlled by a humidistat.’
HeatingO The following advice is given in BS5250:2011
O ‘Having first reduced the amount of moisture in the air as much as possible, energy used to heat the building during cold weather is best applied to heat all internal spaces throughout the day. The risk of condensation is reduced by maintaining a steady, even temperature rather than allowing wide temperature variations in different rooms and/or at different times.’
Design and construction of the building
O Where a material or type of construction has a low resistance to the passage of heat, then its internal surface temperature will be lower than that of a better insulated material or constructional form under otherwise identical conditions. Clearly, this can have an influence on the formation of condensation as lower surface temperatures make condensation more likely.
Mould growth
O Mould spores exist in both the external environment and within buildings in substantial quantities. For these spores to germinate and develop as visible mould certain conditions are required. The removal of any one of these will prohibit mould growth.
Conditions required for mould growth
O Oxygen – always presentO A source of nutrient – most building
materials plus dust and dirt (BRE Digest 370)
O An appropriate temperature – very cold to very warm
O Moisture
Moisture for mould growth
O Different types of mould favour different moisture conditions but relative humidity at a surface of at least 80% sustained for two or three days will generally be sufficient to allow mould spores to germinate. Once established, mould will develop where the relative humidity is maintained at 70% or higher.
Moisture for mould growth (II)
O BS5250:2011:
O ‘Although the symptoms of mould growth may be fairly easily dealt with by either washing with a household bleach diluted 1:4, followed by clean water, or the use of a proprietary toxic wash, it is better to remove the cause of the mould growth, i.e. the high relative humidities.’
The investigation
O Ask the tenant about:O Household sizeO Bathing regimeO Clothes washing and dryingO Use and control of heatingO When people get up and go to bed
The investigation (II)O Check:O Any leaks, rising damp or water
penetration?O WindowsO Trickle ventsO Extract fansO AirbricksO HeatingO Construction
The investigation (III)O Measure:
O Air temperature (thermometer)O Surface temperatures(surface temp
thermometer)O Relative humidity (hygrometer)O Dampness (moisture meter)
‘Dry’, ‘moist’ or ‘wet’ occupancy
O BS5250:2002 Code of Practice for Control of Condensation in Buildings.
O Dry occupancy: where there is proper use of ventilation, it includes those buildings unoccupied during the day; results in an internal pressure of up to 0.3 kPa in excess of the external vapour pressure.
O Moist occupancy: where internal humidities are above normal; likely to have poor ventilation; possibly a family with children, water vapour excess is between 0.3 kPa and 0.6 kPa.
O Wet occupancy: ventilation hardly ever used; high moisture generation; probably a family with young children, water vapour pressure excess is greater than 0.6 kPa.
ConclusionO Islington Council has a duty to take
action to address condensation and other forms of dampness in its housing stock regardless of the cause
O The council is committed to tackling damp and condensation
O LBI’s new condensation protocol lays out the mechanism by which it will meet this duty and achieve this aim