American Aldes Finding Acceptable IAQ with ASHRAE 6222013 User Manual

							60Mechanical Business 04.14
 HigH-performance HVac By Gord Cooke                          • Exciting advances  • The influence of buildin\
g design VENTILATION By Gary Craw                          • Exciting advances  • The influence of buildin\
g design
A
cceptable indoor air quality (IAQ) is dependent on many factors, 
including indoor pollution sources, construction materials, 
furnishings, lifestyle of occupants and outdoor air quality. Acceptable 
IAQ is also impacted by the occupants’ tolerance to indoor pollutants. 
ASHRAE 62.2-2013 should be used as a starting point for the design of a 
ventilation system.  
As ASHRAE 62.2-2013 becomes more prevalent in local and national 
residential building requirements,  it is helpful for everyone involved to

 
become familiar with the basic ventilation requirements of this standard\
.  
ASHRAE 62.2-2013 calls for two mechanical ventilation methods: “whole-
building ventilation”  and “local exhaust.

” Both methods need to be used to 
help achieve acceptable indoor air quality. And keep in mind that ventilation 
equipment is to be rated in accordance with HVI procedures. Remote-
mounted fans are not required to be tested or rated for sound.
ASHRAE 62.2-2013  
Finding AccE\ftAblE iA\b witH 
THE STANDARD
ASHRAE Standard 62.2-
2013 is a ventilation 
standard that defines 
minimum requirements for 
ventilation systems. The 
goal of this standard is to 
achieve acceptable indoor 
air quality (IAQ) for typical 
residences. This standard is 
applicable to single-family 
houses and multi-family 
structures of no more than 
three storeys. The standard 
does not apply to transient 
housing such as hotels or 
dormitories. 
Whole-Building Ventilation  
ASHRAE 62.2-2013 has provisions for three basic mechanical   
ventilation strategies that can be used for Intermittent or continuous  
whole-building ventilation:  
1.Exhaust ventilation
2. Supply ventilation
3. Balanced supply and exhaust ventilation
When selecting the whole-building ventilation strategy that is best for \
an application, 
consideration should be made for local code requirements, geographic location, special 
needs of occupants, and specific indoor and outdoor air quality issues\
. 
ASHRAE 62.2-2013 assumes that all buildings are tight and, as such, does not allow for 
the default assumption of two cfm per 100 sq. ft. that the previous editions did. Rather, it 
requires the use of a blower door to estimate the annual leakage. 
 
teCh tiP   The airflow of all installed ventilation equi\fment that is used to achieve the whole-\building ventilation rate must \be 
measured with an a\f\fro\friate airflow measuring device. 
continues on page 62 
						

							Mechanical Business 04.14
Ensuring a propEr  
v
Entilation ratE 
For intermittently operating whole-buil\fing 
ventilation systems that run at least once every 
three hours\b the time average ventilation rate 
cannot be less than the continuous ventilation 
rate. If the intermittent ventilation system \futy 
cycle (one on an\f off time) is longer than three 
hours\b the require\f ventilation rate increases to 
achieve an acceptable turnover of the air within 
the \fwelling.
62Mechanical Business 04.14
 HigH-perforance HVacBy Gord Cooke                         • Exciting advances  • The influence of buildin\
g design VENTILATION    • Exciting advances  • The influence of building designcontinued from page 60
For continuously operating ventilation systems, ASHRAE 62.2-
2013 provides simple formulas and tables that can be used 
to determine the minimum whole-building ventilation rates. 
This minimum ventilation rate is based on the square footage 
of the dwelling and the number of bedrooms. The number of 
bedrooms is used to determine typical occupancy levels of the 
dwelling. 
This whole-building 
ventilation rate can be 
considered the required 
mechanical ventilation 
rate. Alternatively, the 
whole-building ventilation 
rate may be reduced by 
up to two-thirds to account for the effective annual average 
infiltration rate (Qinf). 
ASHRAE 62.2-2013 provides equations and weather data and 
describes various methods of testing to determine the Qinf for a 
specific dwelling.
Local exhaust 
A local mechanical exhaust system is require\f to be installe\f in each 
kitchen an\f in each bathroom. This local system can be \fesigne\f for 
either continuous or on-\feman\f controlle\f operation. 
The airflow of all installe\f ventilation equipment that is use\f to 
achieve local exhaust rates shoul\f be measure\f with an appropriate 
airflow measuring \fevice. Alternatively\b the airflow rating of 
ventilation equipment at 0.25” w.c. may be use\f if the prescriptive 
\fuct sizing of ASHRAE 62.2-2013 is followe\f. 
The airflow rate of local exhaust systems can also be applie\f to the 
require\f whole-buil\fing ventilation rate requirements\b as long as they 
operate automatically.
For on-\feman\f operating exhaust systems\b the minimum airflow rate 
is 50 cfm for bathrooms an\f 100 cfm for kitchens.
For continuously operating exhaust systems\b the minimum airflow rate 
for bathrooms is 20 cfm. The minimum airflow rate for kitchens is to 
result in five air changes per hour (base\f on kitchen volume). 
continues on page 64 
						

							64Mechanical Business 04.14
 HigH-perforance HVac By Gord Cooke                          • Exciting advances  • The influence of buildin\
g design VENTILATION                    • Exciting advances  • The influence of building designcontinued from page 62
Me\fh Bus News Ad Can\gada_Layout 1  1/23\g/14  1:20 PM  Page \g1E1 Multi HVAC Quar\dter page ad \f4C Mech\da\bical Busi\bess)_Lay\dout 1  2014-
Working with existing buildings  
For existing, occupied, buildings that do not meet the provisions of 
ASHRAE 62.2, an alternative method of compliance is available. 
1. Local exhaust
• If existing exhaust ventilation equipment in bathrooms and kitchens 
does not meet the minimum airflow requirements, the whole-building 
ventilation rate can be increased to offset the insufficient local exhaust 
airflow.
• Existing exhaust ventilation equipment in bathrooms and 
kitchens does not need to be tested to AMCA standards 
or rated to HVI procedures.
• If exhaust ventilation equipment is replaced in bathrooms and kitchens, 
this equipment needs to meet all requirements of ASHRAE 62.2-2013.
2. Whole-building ventilation
• The required ventilation rate for existing buildings may need to be 
increased to offset insufficient local exhaust.
• For existing buildings, if the calculated required airflow rate is less than 
or equal to zero cfm, no whole-building ventilation fan is required.
ASHRAE 62.2-2013 and mul\fi-family \buildings  
For mul\fi-family \building

s: 
1.  Reduc\fions \fo \fhe mechanical ven\fila\fion ra\fe due \fo effec\five
annual averag e 

infil\fra\fion ra\fe (Qinf ) are no\f permi\f\fed.
2.   Common areas are \fo \be ven\fila\fed a\f a ra\fe of 0.06 cfm per sq. f\f.
3.  Non-residen\fial areas of mixed use \buildings are \fo use ASHRAE 62.1.
4.  Common parking garages \fha\f adjoin occupied spaces are required
\fo have exhaus\f ven\fila\fion a\f a ra\fe of 0.4 cfm per sq. f\f.
5.  Specific s\feps need \fo \be \faken \fo minimize \fhe air \fha\f is
\fransferred \be\fween dwelling uni\fs.
6.  The following requiremen\fs are in place \fo preven\f air \fransfer
\fhrough \fhe ven\fila\fion sys\fem:
•  Exhaus\f fans in separa\fe dwellings shall no\f share a common
exhaus\f duc\f. 
•  Exhaus\f inle\fs from  more \fhan one dwelling can use a single exhaus\f 
fan if \fhe fan 

is loca\fed downs\fream of all of \fhe inle\fs and \fhe fan 
 
is run con\finuously, or 

if each inle\f has a \backdraf\f damper.
•  Supply ou\fle\fs \fo more \fhan one dwelling can use a single supply fan 
if \fhe fan is loca

\fed ups\fream of all of \fhe supply ou\fle\fs and \fhe 
 
fan is run con\finuously, or if each ou\fle\f has a \backdraf\f damper. G
ary  Craw  is  Director  of  Engineering  for  American 
A
LDES  Ventilation  Corporation  and  a  member-at-large 
o
f  the  Home  Ventilating  Institute’s  Board  of  Directors. 
T
o learn more, visit  www.aldes.us and  www.hvi.org