A weekly journal on architecture, anthropology and radiant based heating, ventilation and air conditioning. The role of indoor environmental ergonomics, industrial design, HVAC as a health care issue and other human factors in the design of indoor spaces.
The authors review what we know and don’t know about how
thermal comfort and indoor air quality affect performance. The article is
written in the form of answers to 40 frequently asked questions. The authors,
also widely respected, offer opinions based on what the research shows.
Excerpt: “As experienced researchers in the effects of
thermal comfort and indoor air quality on performance, we are often asked to
give our best estimate of how, and to what extent, performance is affected by different
aspects of indoor climate. This article provides a brief summary of our
personal opinions, in the form of answers to 40 frequently asked questions. Our
answers are based on the results of behavioral experiments conducted to date.
We offer no opinions on long-term health effects of indoor environmental
quality. We provide some references to relevant sources, but there is not
enough space for all such references. We list some questions we cannot answer
as topics for future research in this area.”
18 Dec, 2012 10:37 CET Indoor environments that are too hot, too cold or draughty
create discomfort and lower human productivity. MSc (Tech) Riikka Holopainen
from VTT Technical Research Centre of Finland, has written a doctoral thesis on
a new method for estimating the actual level of human thermal comfort in
low-energy buildings. The method is also the first of its kind to be integrated
with a building simulation tool. Factoring in the different ways in which
buildings are used and the different kinds of people using them at the design
stage can help to improve energy efficiency and human comfort.
Energy-efficient passive and zero-energy buildings require
considerably less heating than traditional buildings. Traditional HVAC
solutions are therefore no longer suitable for designing indoor environments
for low-energy buildings.
The Human Thermal Model (HTM) is a new technique developed
by Senior Scientist Riikka Holopainen from VTT in her doctoral thesis, which
can be used to design and create optimal indoor environments for low-energy
buildings. One of the novelties of the method is the fact that it allows
scientists to measure how different solutions are likely to affect human
thermal comfort and the energy efficiency of buildings at the design stage.
The model is based on the physiological thermal control
system of the human body, and it can be used to calculate the actual level of
human thermal comfort in both steady-state and transient thermal environments.
The thesis introduces the first ever mathematical application that integrates a
building simulation tool with human thermal sensation. The model also produces
information about previously complex comparisons, such as the effects of
different structural solutions and HVAC systems on human thermal sensation.
Earlier models for measuring the comfort of indoor
environments have not taken account of the human body’s own thermal control
system. These methods are also insufficient for designing passive and
zero-energy buildings. Models based on laboratory measurements, for example,
overestimate the heat perceived by humans in warm conditions and underestimate
it in cool conditions. They also factor in clothing as a hermetically sealed
unit similar to a diving suit.
Both internal and external factors affect human thermal
sensation. Internal factors include personal characteristics, anatomy, activity
level, whether work is physical, and clothing. External factors include room
temperature, which covers air and surface temperature, as well as air velocity
and relative humidity. Holopainen has demonstrated that the most important
factors contributing to thermal sensation and comfort are air and surface
temperature, activity level and clothing.
Ensuring building
optimisation and human comfort at the design stage
Indoor environments that are too hot, too cold or draughty
create discomfort and lower human productivity. Bed-bound patients in
hospitals, for example, spend a great deal of time lying still and therefore
need a sufficiently warm indoor environment and bedclothes. Checkout operators
in shops, on the other hand, may have to sit in heat in summer and in cold and
draughts in winter. Factoring in the different ways in which buildings are used
and the different kinds of people using them at the design stage can help to
optimise indoor environments and improve human comfort. Employees can also be
given clothing advice.
The Human Thermal Model is suitable for both new builds and
renovations. Engineering firms and the construction industry can now develop
their products to better meet the needs of different buildings and users.
In the future, the HTM and building automation systems will
work together to automatically regulate ventilation, heating and cooling
according to actual needs, incorporating human thermal comfort as an integral
aspect of workplace productivity enhancement.
Source: Holopainen, R., A human thermal model for improved
thermal comfort, Doctor of Science in Technology Thesis, Aalto University, VTT,
December 2012
With ACCA’s Quality Assurance program and these
manufactures and service providers’ commitment to excellence there can be
confidence in the design and installation of radiant based HVAC systems in
America.
Thanks to all.
Robert Bean, R.E.T., P.L.(Eng.) Registered Engineering Technologist - Building construction (ASET) Professional Licensee (Engineering) - HVAC (APEGGA) Building Sciences / Industry Development
Those who still stand firm in the belief that the V in HVAC is exclusively about delivering indoor air quality might want to read this clause:
"A-6.2.1.7.(2) Outdoor Design Conditions. In the past, the practice of ventilating buildings with outdoor air assumed that the outdoor air was of better quality than the indoor air. It has become evident that the outdoor air in some areas of Canada may not be of an acceptable quality for ventilating buildings unless certain particles and gases are first removed or reduced. A recent estimate suggests that 30% of Canadians are exposed to contaminated outdoor air via buildings’ ventilation systems, which may lead to health problems such as cardiovascular and cerebral vascular diseases, respiratory irritation and illnesses, asthma, allergies, cancer, mucus membrane disorders and possibly death."
As we have stated before, the general populations misunderstanding of HVAC is that H is exclusively heating comfort, V is indoor air quality and AC is comfort cooling. This misunderstanding also extends regrettably to a large segment of the construction industry.
This is how we define HVAC:
Heating (H) influences the relative humidity, surface and interstitial vapour pressures, surface temperatures, drafts, material durability, and material VOC emission rates ergo its more than heating for thermal comfort.
Ventilation (V) in and by itself does not guarantee air quality as its function is to exhaust indoor air and replace it with outdoor air. One would think that a higher ventilation rate would be better than a lower ventilation rate but if the outdoor air is contaminated with ozone or has a high humidity, bringing more air in from outside actually makes the inside worse.
Air Conditioning (AC) or conditioning the air allows the designer to treat the air through dilution, filtration, deodorization, temperature regulation, dehumidification, humidification, and air velocity control ergo it is not just cooling for thermal comfort.
Thus, the H in HVAC is not exclusively heating comfort, the V is not exclusively air quality and the AC is not exclusively cooling comfort.
If I had it my way we would change the HVAC to HVCA thus we would have a much better descriptor with Heating, Ventilation and Conditioning of Air.
For a back ground on the topic be sure to read these resources:
Excerpt: "With the aging of the world’s population, researchers have started to focus on creating technologies that can assist with monitoring and ensuring the health and safety of older adults living alone [1]. Much of the emphasis has been placed on detecting falls and ensuring that residents are performing daily activities [10]. On the other hand, there are other factors of an environment which can dramatically impact health. One of these is the air quality of the environment. The World Health Organization [31] reports that 2.4 million individuals die annually from causes directly attributable to air pollution, 1.5 million of these from indoor air pollution. Worldwide there are more deaths from poor air quality than from automobile accidents...The goal of this work is to determine if smart environment sensor data can be used to predict air quality levels. The results we obtained from our study indicate that CO2 levels can be learned with a reasonable amount of accuracy and therefore machine learning models build from sensor data can be used as a partial indicator of dynamic air quality conditions in smart environments. In an ideal scenario CO2 levels would be used with other partial indicators of air quality such as volatile organic compounds for a more holistic quantification of the quality of air in the environment."
RBc: As readers know I am not fan of technology for technology’s sake…the potenetial application for this research however has a useful purpose that benefits families and society in general – that being monitoring the air quality of the environment and ensuring the health and safety of older adults living alone – sounds like a good thing to me.
Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data, and other methods to design in order to optimize human well-being and overall system performance.
The Society furthers serious consideration of knowledge about the assignment of appropriate functions for humans and machines, whether people serve as operators, maintainers, or users in the system. And, it advocates systematic use of such knowledge to achieve compatibility in the design of interactive systems of people, machines, and environments to ensure their effectiveness, safety, and ease of performance. The Society was founded in 1957. It has 23 technical groups and numerous local and student chapters.
RBc: We have featured The Human Factors and Ergonomics Society in the past but want to re-introduce our readers to their work in light of continued development of complicated residential HVAC systems including user interfaces.
Below you find relevant articles on the complications and pro’s and cons of thermostats. If you’re in the business of designing consumer based HVAC products including thermostats these are must read articles.
Excerpt: “It has long been accepted that the physical conditions prevailing in houses exert an influence on the health of occupants.1 Within the UK, the contribution of housing conditions to health inequalities has been recognised in landmark publications such as the Black Report2 and the Acheson Report.3 The health/ housing link is explicitly recognised in the recent Wanless report on public health policy in England,4 which states ‘inequalities in health may be due to . . . social and environmental factors such as housing and income’. A recent (2004) review of evidence conducted by the World Health Organisation5 acknowledges ‘there is considerable evidence that housing conditions do affect health status’. While the domestic may impact on residents’ health via a number of routes, research on the physiological effects of cold environment suggests that low temperatures may be implicated in respiratory conditions6–9 and may be a risk factor for heart disease.10–12”
RBc: As we have been saying since we first launched this blog back in 05’, your indoor environments can be threatening or therapeutic. Be sure to visit our library of research papers addressing this very important topic.
ANSI/ASHRAE Standard 55-2010 is the latest edition of Standard 55. The 2010 edition combines Standard 55-2004 and the ten approved and published addenda to the 2004 edition into one easy-to-use, consolidated standard. The standard outlines conditions in which a specified fraction of the occupants will find the environment thermally acceptable. The standard is intended for use in design, commissioning, and testing of buildings and other occupied spaces and their HVAC systems and for the evaluation of thermal environments.
1. PURPOSE The purpose of this standard is to specify the combinations of indoor thermal environmental factors and personal factors that will produce thermal environmental conditions acceptable to a majority of the occupants within the space.
2. SCOPE 2.1 The environmental factors addressed in this standard are temperature, thermal radiation, humidity, and air speed; the personal factors are those of activity and clothing.
It still amazes me how many people who claim to be part of the thermal comfort industry don’t know that this standard exists. If you’re a designers, builder, manufacturers, tradesperson or building manager and are responsible for keeping people comfortable…you just might want to familiarize yourself with the standard that governs the environments created by your services and products.
Greetings we’re back from our HRAI Indoor Air Quality Awareness Course and able to report the course was another success! To bring readers up to speed I’ve located another science based research report dealing with occupant health and HVAC systems in this case comparing a group of elderly to a group of younger students. The findings, “confirmed that ensuring the warmth of peripheral parts rather than that of the corporal body was important to obtain thermal comfort for elderly subjects and finds that the decrease in peripheral skin temperature and awareness of the coldness of the leg directly reflected thermal comfort for the elderly.” The study also hypothesizes that, “this finding might be one piece of evidence that a floor heating system is a relatively more suitable heating method for the elderly in terms of obtaining efficient thermal comfort, because the floor heating system can produce stable warmth of the leg with relative ease.”
Residential Indoor Air Quality Awareness Course, November 23rd – 25th, 2010, Calgary, Ab.
This 3-day program is a condensed exploration into the numerous elements which influence Indoor Air Quality (IAQ) in residential buildings. Participants will be introduced to the terms of Indoor Environmental Quality (IEQ) and its effect on health and wellness.
The PCA (Prevention, Correction and Avoidance) approach to IAQ is detailed though instruction on the building sciences for cold climates including various options in HVAC equipment and systems. The program also reviews the ASTM Standard D-7297-06, Standard Practice for Evaluating Residential Indoor Air Quality Concerns including a look at various instruments and instrumentation used by investigators.
Included with your registration fee is the 400 page course manual and access to all the instructor slides and the best part is the $200 NRCan subsidy is still available for this course! Seats are limited and filling fast.
We just released our long awaited simplified summary of energy, entropy, efficiency, exergy and efficacy based on our brand new presentation on sustainability and early feedback from industry leaders has been great. It’s all consolidated into a single web page – written of course in basic easy to understand language and linked back to numerous pages within the www.healthyheating.com website.
If you missed the HRAI of Canada’s annual general meeting in Kananaskis, Alberta, saw the sustainability slides posted earlier but wanted the descriptive language – well now you have it.
Abstract Excerpt: In 2004, the first American Heart Association scientific statement on "Air Pollution and Cardiovascular Disease" concluded that exposure to particulate matter (PM) air pollution contributes to cardiovascular morbidity and mortality. In the interim, numerous studies have expanded our understanding of this association and further elucidated the physiological and molecular mechanisms involved.
The main objective of this updated American Heart Association scientific statement is to provide a comprehensive review of the new evidence linking PM exposure with cardiovascular disease, with a specific focus on highlighting the clinical implications for researchers and healthcare providers.
RBc: “…exposure to particulate matter (PM) air pollution contributes to cardiovascular morbidity and mortality.” Once again environments can be hurtful or healing – you have little control over the outdoor conditions but you do have a choice over your indoor environment.
See our previous comments on homes as miniature health care facilities and the need to reposition elements of architecture such as interior design and HVAC as part of the healthcare industry and removed out from under the control of the construction industry.
Air Pollution and Seniors - A Health and Air Quality Bulletin from Health Canada
Further to our post below on Blueprints for Senior Living July 2010 Edition, we bring your attention to a Health and Air Quality Bulletin from Health Canada.
Excerpt: If you are a senior, air pollution could have a negative impact on your health. This is because seniors are more likely than other adults to have health problems such as heart and lung disease. You can better protect yourself when you know that air pollution affects your health.
Also, published recently from Statistics Canada’s Canadian Community Health Survey: Healthy Aging The Canadian Community Health Survey focuses on the health of Canadians aged 45 and over by examining the various factors that have an impact on healthy aging, such as general health and well being, the use of health care services, social participation, and work and retirement transitions. The data were collected from December 2008 to November 2009, and about 30,900 individuals aged 45 years and older in the provinces were interviewed. The data are now available through the Statistics Canada website: http://www.statcan.gc.ca/daily-quotidien/100512/dq100512f-eng.htm
The mission of the AIA Design for Aging Knowledge Community (DFA) is to foster design innovation and disseminate knowledge necessary to enhance the built environment and quality of life for an aging society. This includes relevant research on characteristics, planning, and costs associated with innovative design for aging. In addition, DFA provides outcome data on the value of these design solutions and environments.
For more information about the Design for Aging please contact your local chapter or the Design for Aging Advisory Group. More information can be found on www.aia.org/dfa or www.aiadesignforaging.org.
RBc: We've been a big fan of this group for the insight and creativity they bring to this very special topic. A highly recommended resource worthy of your support.
See our pages on Design for Aging and be sure to read the abstract titled, "Supportive living environments: A first concept of a dwelling designed for older adults with dementia."
Overview/edited excerpt: Results from naturally ventilated buildings show that allowing the indoor temperature to drift does not necessarily result in thermal discomfort and may allow for a reduction in energy use. However, for stationary conditions, several studies indicate that the thermal neutral temperature and optimum thermal condition differ between young adults and elderly.
In this study, the effect of a moderate temperature drift on physiological responses, thermal comfort, and productivity of eight young adults (age 22–25 year) and eight older subjects (age 67–73 year) was investigated. They were exposed to two different conditions and the results indicate that thermal sensation of the elderly was, in general, 0.5 scale units lower in comparison with their younger counterparts. Furthermore, the elderly showed more distal vasoconstriction during both conditions.
Practical Implications
Because the stock of fossil fuels is limited, energy savings play an important role. Thermal comfort is one of the most important performance indicators to successfully apply measures to reduce the energy need in buildings. Allowing drifts in indoor temperature is one of the options to reduce the energy demand. This study contributes to the knowledge concerning the effects of a moderate temperature drift and the age of the inhabitants on their thermal comfort.
RBc: This document does an effective job in pointing out the differences between age groups as it relates to indoor environments and the corresponding physiological and psychological responses to temperature changes.
We have said before that the traditional run of the mill contractor built home was/is constructed for the youth and not the elderly and yet it will be the elderly that someday will occupy these homes.
We have pointed out before that residential homes will become miniture healthcare centers for the elderly and have asked, “if we know a home will be operated as a miniature healthcare center why don’t we build it as such?” What does this mean? It means designing to healthcare standards with better ventilation and thermal comfort systems…instead of budgeting a meager 5% of construction costs on HVAC it means you have to spend 15%.
5% gets you bottom of the barrel minimum requirements…15% gets you into healthcare standards.
Established in 2004, The Journal of Indoor Environmental Quality (JIEQ) in conjunction with Healthy Heating serves as a technical interpreter and consolidator of academic research demonstrating the building and health sciences are inclusive elements. It provides professional development programs based on its analysis to application professionals such as architects, engineers, interior designers and related technicians.
Subscribe to the JIEQ
Visit www.healthyheating.com
Friends of Industry
Quotes
“The quality of housing conditions plays a decisive role in the health status of the residents, because many health problems are either directly or indirectly related to the building itself, the construction materials that were used, and the equipment or the size or structure of the individual dwellings.”
The World Health Organization
"Indoor environmental quality is in part a result of materials and methods of construction which has an influence on occupant health. For this reason, policies around health and construction cannot be treated separately and must be linked together." Source: Bean, R., IAQ Webinar Presentation, 2009
The HVAC system consumes 50-60% of the building energy cost and generates 80-85% of tenant complaints.
Source: U.S. General Services Administration, Public Buildings Service, Office of the Chief Architect
Good Design
“Industrial designers determine the form and interaction qualities of manufactured products...They study people at work, at home and in motion to create satisfying experiences with products from the kitchen and the office to the hospital and the warehouse…” Excerpt from the Industrial Designers Society of America (IDSA).
In our opinion, industrial design has been overlooked by the HVAC industry – illustrated by consumers facing difficulties selling homes with HVAC systems which have “beast in the boiler room.”
Be reminded by S. Claire Conroy from Residential Architecture, "It's time architects of every discipline understand residential architecture for what it really is: everyone's most intimate connection with architecture. It's not simply a “test bed”—it's a vessel for our lives on their most personal level. That makes the stakes very high indeed. No one is more discriminating and demanding than a residential client.”
"A lot of it has to do with how we are responding at a physiological level to what we see as we walk in through the door." Sarah Susanka, Architect
“Industrial designers determine the form and interaction qualities of manufactured products...They study people at work, at home and in motion to create satisfying experiences with products from the kitchen and the office to the hospital and the warehouse…” Excerpt from the Industrial Designers Society of America (IDSA).
"In any industry, one of the most important and difficult tasks is to explain a nuanced process to someone unfamiliar with the field. At its grass roots, design is a process like many others; it has theories, strategies and examples that can be explained on a general level. It’s not a matter of what type of information is given, but rather how it is presented and to what type of audience."
Speaking Design to Non-Designers, IDSA
