Prof Tim Sharpe

Ventilation in Homes: A breath of fresh air?

• EPSRC Assessment of Environmental and Energy effects of Domestic Laundering (100 + 40

houses)

• AHRC Study, sunshine and well-being in housing (40 houses)

• Scottish Building Standards - Guidance for Occupants of Low Energy Homes

• Technology Strategy Board (Innovate UK) Building Performance Evaluation Programme • Expert Evaluator

• The Glasgow House (Phase 1)

• Inverness expo (8 houses)

• Bloom Court Livingston (2 + 6 houses)

• Ti-na-Cladich, Dunoon (3 houses)

• Queens Cross, Glasgow (6 houses)

• Murray Place, Barrhead (3 houses)

• Knowledge Transfer Partnership with Cartwright Pickard Architects, London (20 houses on 5

sites)

• Meta study of MVHR system in Domestic properties

• Scottish Building Standards - Research Project To Investigate Occupier Influence On Indoor Air

Quality In Dwellings (200 + 40 houses).

Relevant recent projects

• 3 year EPSRC funded study, MEARU lead

• Investigated the laundry habits + detailed analysis of air quality and energy

consumption relative to domestic laundering habits.

• Indoor clothes drying is commonplace

• Internal clothes drying delivers large amounts of moisture into a dwelling

• http://www.homelaundrystudy.net

Environmental Assessment of Domestic

Laundering

Sunshine, Health and Wellbeing in Housing

• Hypothesis that good access to sunlight in the home will have a positive influence on

general health and wellbeing.

• Measure of IAQ and testing for spores

• The relationship between sunlight opportunity and psychological well-being is positive

and significant

Guidance for Occupants of

Low Energy Homes

• Simple guidance for occupants of low energy homes for Scottish Building Standards

• Originally part of Silver standard for Section 7

• Now included in mainstream regs 2015

• http://www.gov.scot/resource/doc/217736/0116377.pdf

Knowledge Transfer Partnership

• Knowledge Transfer Partnership with Cartwright Pickard Architects

• Developing light-touch BPE methodology

• 20 Houses, 2 week monitoring 3 seasons

• Ventilation and IAQ issues

TSB Projects

• £8m Innovate UK funding – 2010 to 2014 - total

four year programme of project activity

• Domestic: 53 projects (350 dwellings)

• 23 Phase 1 projects

• Post construction & initial occupation

• 30 Phase 2 projects

• In-use performance & post occupancy

evaluation

• Non–domestic: 48 projects (55 study buildings)

• 8 Under construction & early occupation

• 40 In-use

Ventilation in BPE study houses

• MEARU engaged in monitoring 7 domestic

projects in Scotland

Meta study of MVHR system in

Domestic properties

• To gather and analyse the available performance

data

• To gather information about performance, and how

they are being maintained and used

• To share this information within projects and to the

wider construction industry

Research Project To Investigate Occupier Influence On

Indoor Air Quality In Dwellings

Prof Tim Sharpe MEARU

Jonathan McQuillan Anderson Bell Christie

Dr. Stirling Howieson, University of Strathclyde

Paul Farren ASSIST DESIGN ARCHITECTS

Dr. Paul Tuohy ESRU, Strathclyde University

Aims

• To investigate occupants interaction with trickle vents and windows

• Identify the frequency and drivers/barriers

• What are the effects of these interactions?

• Does the existing provision work?

Methodology

• Literature review • Health effects and ventilation

• Similar studies

• What is an accepted measure of ventilation?

• Large scale survey • 200 households of recent (post 2010) houses

• Door step survey asking about ventilation habits

• Subsurvey • Selection of >50 of these properties for monitoring

• Temp, CO2 and RH for a 48 hour period, along with survey and observations

• Core survey • Extract data from long term monitoring of 26 houses in TSBP BPE programme

• Week long observation of data with occupant diaries

• VOC and particulate testing in some properties

Literature review

• Increasing concern over IAQ

• Ventilation rates decreasing due to energy drivers - air tightness testing

• CO2 used as a proxy measure - indicative of ventilation rate ‘bad company’

• Produced by occupants - no direct relation to VOC - depends on source

• Clear associations between health effects + poor ventilation (evidenced through high

CO2)

• General consensus with 1000 ppm (8 l/s/p) as a measure of IAQ acceptability

• Numerous studies relating poor ventilation with health issues

• Fewer studies in housing

• “..ventilation rates above 0.4 h-1 or CO2 below 900 ppm in homes seem to be the

minimum level to protect against health risks based on the studies reported in the

scientific literature” Wargocki, P. The Effects of Ventilation in Homes on Health. Int. J. Vent. 2013; 12, 101–118.

• 1000 ppm is therefore used as a threshold level for ventilation

Overview Survey

• Series of questions asking occupants about their ventilation habits

• Trickle vents are supposed to provide a level of background ventilation

Overview Survey

• 83% knew what it was and what it was for

• Most people know what it is for

How often do you open your trickle vents?

• Vast majority keep them closed

• About a quarter keep them open

• Very few change them

• Only about 1% change them daily

Overview Survey

Barriers?

• Most people don't feel the need to

• Lack of knowledge - 82% had received no advice on ventilation

• Worries about draughts/heat lost also significant

Overview Survey

Opinions on air quality?

• Lack of need corresponds to occupants perception of air quality

• Most people didn't think there was a problem

Overview Survey

How often do you open windows?

• Much more frequent interaction

• Daily as well as weekly

• <20% never open them

Overview Survey

Barriers and Drivers?

• Overheating principle driver for

window opening

• Removal of moisture or smells also

significant (compare with perception

of IAQ)

• Concerns about leat loss main

reason for not opening windows

Overview Survey

Bedroom window opening

• 78% people keep bedroom windows closed

• Habitual rather than adaptive

• Door opening important

Overview Survey - Summary

• Trickle vents

• Regular interaction with trickle vents very low

• Either open of closed - mostly closed

• Windows

• More use of window opening (designed to be opened)

• Window driven by temperature rather than IAQ (perceptions)

• Concerns over heat loss important in both cases

• IAQ not perceived to be a problem (cf Carbon Monoxide)

Sub-survey

What are the effects of these strategies and habits?

• Took sub-set of 50 properties

• Conditions monitored as reported in initial survey

• Information on the household

• Observations

• Trickle vent open/closed

• Window open/closed

• Door open/closed

• Number of occupants

Sub-survey

• Focus on bedrooms

• Living room occupancy intermittent

• Other confounding factors

• Focus on bedrooms

• Clear periods and intensity of occupation

• Of interest due to the occupied length of time

Sub-survey

Sub-survey

• Effects of occupancy, vent and window opening

• Open windows a clear mitigating factor

• Vent open conditions are better, but not good

• With 1 occupant condition better, but still over >1000 ppm

• All bedrooms classed a double bedrooms

Sub-survey

• Effects of door opening

• Door and vents open gives the best outcome - but rare

• But all > 1000 ppm

Sub-survey

• Air change rates calculated from

CO2 levels, volume and occupancy

Sub-survey

• Large range, some OK for moisture control (0.5 ach) but 42% below

• None OK for IAQ = 8 l/s/p

Average bedroom CO2 level v. ventilation rate per person and Average bedroom CO2 level v. bedroom air change rate

Sub-Survey

Observations

• Trickle vents are frequently out of immediate reach due to height, furniture and

positioning of blinds and curtains.

Sub-Survey

Observations

• The majority of bedroom windows surveyed have some

form of blinds or curtains that would occlude the vents,

especially at night when curtains and blinds are most

used.

• No instances where vents had been interfered with or

blocked

Sub-Survey

Observations

• Floor coverings frequently obstructed door undercuts - residents comments including

that they had to physically shorten doors to allow opening after fitting carpets

Sub-Survey

Observations

• Placement of trickle vent controls differs from window handles, which are required to

be in an accessible position

Sub-Survey

Observations

• Noticeable cold air from vents - radiators not under windows

Summary

• All rooms had levels above 1000 ppm

• Night time window opening a clear mitigating factor

• Allowing for occupancy:

• Trickle vent opening improves vent rates, but by marginal levels

• Door opening a mitigating factor

• But in both cases large amounts of time over 1000 ppm

Detailed monitoring

• 29 houses monitored as part of TSB BPE programmes

• Across Scotland

• 2 years monitoring of energy, temp, RH and CO2

• Air-tightness:

• All but one below 10 m2/m3.h @ 50 Pa

• Excluding Passivhaus (which have MVHR):

• 12 out of 21 are below 5 m2/m3.h @ 50 Pa - don't have mechanical ventilation

Detailed Monitoring

• Sample period of 7 days - trickle vents open

• Some window opening

• Confirms findings of sub-survey

Detailed Monitoring

• Rooms with windows closed

• Trickle vents open

CO2 levels and CO2 intensity (% t >1000 ppm) by door opening and occupancy exc window opening

Detailed Monitoring

• VOC and particulate monitoring

• Effects of ventilation on pollutants

• High levels of VOCs not noted (monitoring on-going)

• However clear correlation between CO2 and Formaldehyde

CO2 & Formaldehyde in bedroom of IB1 and LA1 over 48 hours.

Conclusions

• Little interaction with trickle vents

• Window use more frequent, but used for purge ventilation

• This does not occur in bedrooms

• Some people are habitual bedroom window openers

• Drivers for window opening are adaptive responses to temperature

• Barriers are heat loss/cost

• Knowledge and usability are issues

• Little perception of poor IAQ (bedroom effects)

• Limited knowledge about ventilation needs/provision/strategies

Outcomes

Revision of the Guidance?

• Guidance becomes the standard - limits innovation

• Recognition of varying built forms. e.g. single aspect

• Modifications (increased trickle vent size, door undercuts) unlikely to be effective

Revision of the Standards?

• What is the measure of success?

• Set standards and let designs find solutions?

Revision of Compliance?

• Greater need for compliance checking

• Reliance on mechanical does not guarantee solutions or compliance

Thank you

• Tim Sharpe t.sharpe@gsa.ac.uk 0141 353 4658