Thermal Comfort

“Good temperature is the one you don’t notice at all”

Our thermal comfort defines not only our well-being but our physical and intellectual performance.

There are many factors that effect human thermal comfort, such as air temperature, temperature of surfaces, humidity, and air movement. All of the above may be grouped under "environmental variables". "Personal" variables such as clothing insulation value ["clo" value] and the metabolism rate ["met" value] are also important components when calculation individual thermal comfort.

http://www.design.asu.edu/radiant/01_thermalComfort/comfortC_01variables.htm

Each of the above influences how we feel in a given volume of air. To reach a

desirable level of comfort some or all of the factors may be manipulated. Sometimes one of them may be changed instead of the other. For example, instead of raising the temperature to make the space feel warmer for people with a low physical activity, humidity may be raised. In order to understand what thermal comfort is and how it effects us we had to review some of the terminology:

Relative humidity - is the percentage of water in air compared to the maximum the air can hold. For ideal comfort relative humidity has to be kept low in hot temperatures/climates.

High humidity (60% or above) might become a serious issue in extreme climates as it could cause condensation, destroy/decompose materials that can hold water, and even promote growth of microbes. Low humidity (20% or less) can cause health problems such as dry nose and throat nosebleeds, or may cause problems with not very stable materials, such as shrinking, etc.

Air movement accelerates evaporation process when touching a surface. When touching human skin through evaporation it cools the body influencing our thermal comfort. Air movement may be increased when instant cooling is needed. To maintain a comfortable space without drafts the air movement should be kept between 10-15 cubic feet per minute.

In last class we also discussed such terminology as:

Thermal capacity – the ability of a material to sore heat proportional to materials mass and weight.

Thermal resistance – how fast heat transfers through a material. For example, materials with low resistance cool or hear rapidly, and material with high thermal resistance may be used to absorb the heat during the day and releasing it into the space during the night to heat it up (methods used in deserts)

Heat lag – explains gap in temperature, it is the time it takes for heat to travel through a material.

Core body temperature – 37C (98.6F).

· People perform best id the room temperature stays the same most of the time

· ¾ of the body heat is released by human body just to keep it warm. The rest is used to move it. At the same time, the more body moves – the more heat it generates. That means that the more body moves the warmer it stays and more the space is warmed up by the body, which must be considered when designing spaces for active physical activities by calculating space volume, nunber of people, and an average metabolic rate

Metabolic rate – rate at which energy is used based on activity

Thermal equilibrium – a material is at thermal equilibrium when there is no energy/heat transfer between the material and its surroundings

Heat transfer – a travel of heat from higher temperature surfaces to lower temperature surfaces. For example, in winter the cold surface of a window “sucks in” the heat from the material and bodies in the interior of the room

Thermal dynamics – heat movement

· Convection – movement of active warm air molecules to cooler areas. For example, when air moves pass our body it observes its energy/heat

· Conduction – heat transfer through direct contact with cool surfaces. For example, as we stem on cold stone floor our body heat quickly starts moving from out body to the stone material

· Radiation – heat radiates to cooler surfaces without any physical contact

· Evaporation – transformation of a material from liquid to gas during which gas absorbs heat energy

Reflectance/Absorbance – ability of heat to be reflected off light surfaces and absorbed by dark surfaces

Keeping in mind the discussed above building envelope and joining elements of a new building constructed bust be determined individually based on climate and site conditions. Thermal breaks must be correctly done between the building envelope and materials. Thermal bridge, using the qualities of heat discussed above might let the cold (or hot) air transfer from the outside of the building in its inside (which is not desirable) through such elements as metal joints. To make correct decisions designer must know the conditions he/she is building in, the qualities of the materials used, and the general physics of air and moisture movement

Thermal comfort is hard to visualize but it may be illustrated with mathematical formulas or charts. This is an awesome illustrated website with "simple" mathematical formulas that explains what is thermal comfort, its values, conditions, and how to calculate it. The website highlights what to measure and pay attention to when calculating thermal comfort and explains all the factors that have to be taken into account such as physical activity factors, clothing factors, temperature and humidity factors, etc: http://www.blowtex-educair.it/DOWNLOADS/Thermal%20Comfort.htm :

I personally like Willis Carrier's Psychrometric Chart that he developed over one hundred years ago trying to help people visualize the relationship between the air temperature and relative humidity that always exist in space. this chart is the basis of the air conditioning industry.

The chart outlines conditions at which most people are comfortable at. Winter and summer comfort zones are shown separately. It should be taken into account that different amount/kind of clothing is worn during this two different seasons.

It may be concluded from the chart above that the temperature where most people would be comfortable at year round would be around 74F which is about 23C.

Green Building Approaches

October 9th field trip 303 Portage Avenue - Mountain Equipment Co-op and 586 Ellice Avenue - West End Cultural Centre. On this field trip we have visited these two sustainable building structures.
The MEC building was constructed out of two deserted buildings that were converted to one environmental sustainable building. This building incorporates features such as, locally sourced materials, rooftop garden, and rainwater collection system. For the MCE construction all structural materials in this building were reclaimed from the other two buildings, including the brick and wood floor, joists, exterior masonry, cast iron columns and steel beams. These materials were inventoried, sorted and cleaned and the design of the new building was based on these materials. MEC minimized use of interior finishing for example they used limited painted surfaces, exposed brick walls, floor, wood and avoided using unnecessary materials. The new building is 97% reused and recycled material. Use of salvaged and refurbished materials in new building extends the life of materials and adds character to the building.
The MEC includes: energy efficiency, embodied energy, landfill diversion and CO2 emissions. CO2 detectors located in each zone and there are 19 zones in the building that ensure an optimal balance of fresh incoming air, so energy isn't wasted in heating or cooling. To reduce heat loss and energy consumption, exterior building walls are insulated. A green roof provides evaporative cooling and helps insulate the building to reduce energy required for heating or cooling. Storm water from the green roof is collected in two 5700 L storage tanks. Collected, stored water is used to irrigate the roof, via a solar photo-voltaic powered pump, with the flow being proportional the solar heat gain on the roof. Composting toilets provide fertilizer that is used in rooftop garden.
The MEC building is build in such way that it can be easily taken apart or disconnected.



The West End Cultural Center is 101 years old former church that recently went through redevelopment of designing a building that would be environmentally sustainable. It is based on 3 principles reduce, reuse and recycle. The WECC accommodates many environmentally-friendly features, that include a geothermal heating system that will reduce energy consumption for heating and cooling, low flow toilets, high efficiency windows and upgraded insulation to help reduce heat loss. More than 85% of the materials from the old building were reused. Also, a great deal of the construction materials used on site were made with recycled material. The bathroom countertops were created out of toilets, sinks, as well as wine and beer bottles all recycled locally. A lot of materials like doors, partitions, floor boards, joist, and bricks were used from the old building and some materials were given to WECC from other buildings. The theatre seats from the former Epic Theatre, solid oak doors, windows and bathroom partitions came from a Calgary courthouse. High efficiency T8 fluorescent lighting incorporated throughout the building for better energy saving.
Before the redevelopment the WECC building had a lot of major problems: it was not wheelchair accessible, washrooms were not up to code, and it had not designated community programming space. As building got redeveloped it had to meet three goals:
• Be structurally sound and environmentally sustainable: meet building code standards for accessibility and amenities such as washrooms.
• Have increased physical capacity: Increase concert seating from 300 to 400, add community hall seating, and expand the lobby area.
• Offer improve programming and patron facilities: a large stage, new sound and lighting technology, better facilities for artists, patrons and community programming participants.
Now the West End Cultural Centre’s new home became a better place for patrons, artists, for the community and the environment.

September 28 - Considerations for design

This is a late entry for the lecture on September 28. The lecture was about building regulations, building codes and basically the things you need to comply with to get your design approved and through construction.

Our project of relocating the King’s Head Pub building to the Forks is considered a major alteration. It entails occupancy changes (A) and the process of bringing the existing building to modern codes (B). The details of this depend entirely on our individual decisions for the assignment.

Exchange district and the Forks are located in two different zones so different zoning requirements including different kind of land use, bulk, signage, parking, loading and urban design need to be considered.

A. Building occupancy classifications refer to categorizing structures based on their usage and are primarily used for building and fire code enforcement. Many buildings may have multiple occupancies. These are referred to as "mixed occupancies" and the different parts will be required to meet the codes for those specific areas. In places where more than one occupancy may apply the stricter code is usually enforced. source

The following classification is based on the International Building Code:

Assembly (Group A): places used for people gathering for entertainment, worship, and eating or drinking. (churches, restaurants, theaters, and stadiums)
Business (Group B): places where services are provided. (banks, insurance agencies, government buildings (including police and fire stations), and doctor's offices)
Educational (Group E): schools and day care centers up to the 12th grade.
Factory (Group F): places where goods are manufactured or repaired. (factories and dry cleaners)
High-Hazard (Group H): places involving production or storage of very flammable or toxic materials. (places handling explosives and/or highly toxic materials)
Institutional (Group I): places where people are physically unable to leave without assistance. (hospitals, nursing homes, and prisons)
Mercantile (Group M): places where goods are displayed and sold. (grocery stores, department stores, and gas stations)
Residential (Group R): places providing accommodations for overnight stay. (houses, apartment buildings, hotels, and motels)
Storage (Group S): places where items are stored. (warehouses and parking garages)
Utility and Miscellaneous (Group U): others. (water towers, barns, towers)

B. The Manitoba Building Code is a set of minimum requirements intended to protect health, safety and structural sufficiency in buildings. It deals with new construction, including additions and major alterations. It is intended to apply to high rise and low rise buildings used for residential, business, mercantile, industrial and assembly occupancies. source

The lecture also covered the elements to be considered for fire safety, designing exits, health requirements and access requirements. The detailed requirements for these can all be found in part C of NBCC (National Building Code of Canada) or The Manitoba Building Code described above which is based on NBCC.

Occupancy load which is the estimated number of people on each floor has a great impact on exit design. The number of exists, their location and width and the distance between them are factors to be decided on. There must be at least two exits on each floor. In the King’s Head Pub, they closed the second exit on the second floor and opened one in the adjacent building. We need to open it up again in the new location for our studio assignment.