Page 62 - GRIHA Manual Volume III - Introduction to National Rating System
P. 62
Building and system design optimization 55
1. Heating, ventilation, and air-conditioning: Under this section, the mandatory clauses establish
requirements for natural ventilation, minimum equipment efficiencies, installing controls for
all mechanical cooling and heating systems, insulation standards for piping and ductwork,
and guidelines for system balancing and condensers. Standard for natural ventilation ensure
comfortable conditions for building occupants. Minimum equipment efficiencies, equipment
controls, piping and ducting insulation, and so on, ensure maximum efficiency for the HVAC
system.
2. Solar hot water heating systems: Under this section, various factors are elaborated on sizing,
efficiency, insulation, and system requirements for solar water heaters.
3. Artificial lighting: The mandatory clauses for artificial lighting emphasize the use of lighting
controls for building interiors and specify the minimum efficacy requirements for outdoor
lighting.
4. Electrical power: The mandatory clauses for electrical power provide minimum specifications for
transformers, energy-efficient motors, power correction factors, metering and monitoring, and
power distribution losses.
Following ECBC compliance clause is a prescriptive requirement in ECBC, and not a mandatory
clause. However, in GRIHA, this compliance has been made mandatory.
5. Fenestration: The effective SHGC of the fenestration (accounting for glazing, overhangs, and/or
vertical fins) is compliant with the maximum SHGC requirement prescribed by ECBC-2007.
Note: For information on all the compliances mentioned above, please refer to the ECBC-2007 document.
2. Thermal comfort standards
Thermal comfort refers to a condition of the thermal environment under which a person can
maintain body heat balance at normal temperature without perceptible sweating. Human thermal
comfort is dependent on the following four environmental and two physiological factors.
# Environmental factors
• Dry bulb temperature
• Mean radiant temperature
• Relative humidity
• Air movement
# Physiological factors
• Metabolic rate
• Clothing level
Thus, a person’s heat loss and his/her feeling of comfort depend on air temperature, air movement,
humidity levels in the air as well as mean radiative gains. In India, according to the NBC-2005,
Bureau of Indian Standards (BIS), thermal comfort of a person lies between 25 ºC and 30 ºC, with
optimum condition being 27.5 ºC.
There are various advantages of maintaining the required thermal comfort conditions for building
occupants. Physical comfort is critical to effectiveness, satisfaction, and physical and physiological
well-being. Uncomfortable conditions (too hot, too cold, and so on) have a negative effect on the
productivity of building occupants.
1. Heating, ventilation, and air-conditioning: Under this section, the mandatory clauses establish
requirements for natural ventilation, minimum equipment efficiencies, installing controls for
all mechanical cooling and heating systems, insulation standards for piping and ductwork,
and guidelines for system balancing and condensers. Standard for natural ventilation ensure
comfortable conditions for building occupants. Minimum equipment efficiencies, equipment
controls, piping and ducting insulation, and so on, ensure maximum efficiency for the HVAC
system.
2. Solar hot water heating systems: Under this section, various factors are elaborated on sizing,
efficiency, insulation, and system requirements for solar water heaters.
3. Artificial lighting: The mandatory clauses for artificial lighting emphasize the use of lighting
controls for building interiors and specify the minimum efficacy requirements for outdoor
lighting.
4. Electrical power: The mandatory clauses for electrical power provide minimum specifications for
transformers, energy-efficient motors, power correction factors, metering and monitoring, and
power distribution losses.
Following ECBC compliance clause is a prescriptive requirement in ECBC, and not a mandatory
clause. However, in GRIHA, this compliance has been made mandatory.
5. Fenestration: The effective SHGC of the fenestration (accounting for glazing, overhangs, and/or
vertical fins) is compliant with the maximum SHGC requirement prescribed by ECBC-2007.
Note: For information on all the compliances mentioned above, please refer to the ECBC-2007 document.
2. Thermal comfort standards
Thermal comfort refers to a condition of the thermal environment under which a person can
maintain body heat balance at normal temperature without perceptible sweating. Human thermal
comfort is dependent on the following four environmental and two physiological factors.
# Environmental factors
• Dry bulb temperature
• Mean radiant temperature
• Relative humidity
• Air movement
# Physiological factors
• Metabolic rate
• Clothing level
Thus, a person’s heat loss and his/her feeling of comfort depend on air temperature, air movement,
humidity levels in the air as well as mean radiative gains. In India, according to the NBC-2005,
Bureau of Indian Standards (BIS), thermal comfort of a person lies between 25 ºC and 30 ºC, with
optimum condition being 27.5 ºC.
There are various advantages of maintaining the required thermal comfort conditions for building
occupants. Physical comfort is critical to effectiveness, satisfaction, and physical and physiological
well-being. Uncomfortable conditions (too hot, too cold, and so on) have a negative effect on the
productivity of building occupants.
