zigmark said:
In Washington State the heating system sizing forms are provided for use by the state through a Washington State University program started many years back. Just recently this State has started moving toward using the IECC by incorporating the States' amendments into that document. Here is a link to the excel program that is used;
www.energy.wsu.edu/Documents/Prescriptive%20Worksheet%20Both%20Zones.xlsxwww.energy.wsu.edu/Documents/2012%20Glazing%20Schedule.xlsx
www.energy.wsu.edu/Documents/Heat_Sizing_code%20specs_final.xls
www.energy.wsu.edu/Documents/Table_406_2_Energy_Credits_2012_WSEC.pdf
The last link is to the explanation of required energy credits a home owner must incorporate into their building. So depending upon the size of the proposed construction they are required to obtain between 1.0-2.5 credits from the options listed.
We require them to submit this information at plan review. As previously stated the systems were often oversized prior to this being implemented. We still occasionally get a heating contractor that wants to argue about a systems ability not being able to heat the proposed structure so they don't have to sell a less expensive model.
ZIG
Unfortunately not only do the contractors in the HVAC industry not have the knowledge base to properly design install and commission heating and air conditioning equipment, it appears that individuals in the code enforcement industry also have a long way to go in understanding and implementing good industry practice.
A code proposal was presented to change the criteria for load calculations for comfort cooling that was rejected numerous times and at different state and national levels. It was again rejected at the code hearings recently held in New Jersey, and put up for a floor vote and passed.
This is a clear indication that enough people where gathered to vote on something that they had no competent knowledge about the subject matter.
If this code change is not one reversed, "this will take time but will happen" it should be rejected at every state level and not adopted. This is only going to lead to worse situations than are already becoming apparent to consumers on the performance of there heating and cooling systems, not to mention the excess wear and tear and increased maintenance of the equipment and the excess electricity that will need to be produced to satisfy the demand.
RM9 – 13
M1401.3
Proponent:
Richard Grace, Fairfax County VA,
representing
The Virginia Plumbing and Mechanical
Inspectors Association and the Virginia Building and Code Officials Association
Revise
as follows:
M1401.3
Equipment/
appliance
Sizing
.
Hea
ting and cooling equipment and appliances shall be sized in
accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J
or other approved heating and cooling calculation methodologies.
Exception:
Heating and cooling equipment and appliances shall not be limited to the capacities
determined in accordance with Manual S where any of the following conditions apply:
1.
The specified equipment or appliance utilizes multi
-
stage technology or variable refrigerant flow
te
chnology and the loads calculated in accordance with Manual J fall within the range of the
manufacturer’s published capacities for
that equipment or appliance.
2.
The specified equipment or appliance manufacturer’s published capacities cannot satisfy
both
the total and sensible heat gains calculated in accordance with Manual J and the
manufacturer’s next larger standard size unit is specified.
3.
The specified equipment or appliance is the lowest capacity unit available from the specified
manufactu
rer.
Reason:
Item 1
-
Current technology is widely available that incorporates multi
-
stage or VRF systems for increased efficiency.
Some of these appliances have such a wide span of functionality that they extend beyond the allowable requirements outlined
in
Manual S. However, this technology allows the appliance to operate between minimum and maximum capacities, based on loads
imposed, thus eliminating the problems associated with single
-
stage, oversized appliances. Additionally, the appliance will operat
e
efficiently during times where outdoor air temperatures exceed those used to calculate the loads in Manual J.
Item 2
-
Often times, the appliance manufacturer’s published total and sensible capacities are at odds with the requirements of
Manual S. There
are many cases where the total capacity of the appliance will fall within the parameters of Manual S in relation to
the calculated total gain, however the sensible capacity of the appliance may fall short of the calculated sensible gain, thus unable to
pr
ovide efficient sensible cooling for the space. When the manufacturer’s next standard size larger is chosen to meet the sensi
ble
gain, the total capacity of the appliance may then exceed the requirements of Manual S. Choosing the larger appliance will en
ab
le a
more efficient and effective system.
Item 3
-
The current code language does not have provisions for sizing appliances for minimal dwelling unit or dwelling addition
loads, other than forcing owners and contractors to change appliances to less desirable systems. For example; a 2 story townhouse,
in climate zone 4, with 600 square feet per floor wants to utilize a two
-
zone system, or a separate heat pump system for each floor.
A 1.5 ton unit per floor would exceed the requirements of Manual S, however
a 1.5 ton unit could be the smallest available appliance
made by the desired manufacturer. Current language would require a complete design change, such as utilizing a single applian
ce
to serve the entire dwelling rather than the more desirable two
-
zone system, or requiring a system that utilizes electric baseboard
heating and window
-
mounted air conditioning units. This is absurd, and an unfair to an owner that desires to reduce energy costs.
Cost Impact:
none
RM
9-
13
Public Hearing:
Committee:
AS
AM
