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3 AMERICAN
HEATING
\"('I f^ INC
5035 SE 24th Avenue, Portland,Oregon 97202
ri t V, i`�i`�.• P 1 503.239.4600 Fl 503.239.7038
BUILT ON TRUST OREGON CCB:33135 I WASHINGTON AMERII*212JC/AMERIHI123R0
TO: City of Tigard Building Division
ATTN: Walter Chip Barnett
FROM: Brian Shea and Mac Nelson
DATE: October 19, 2016
PROJECT: Burnham and Ash Apartments
SUBJECT: Refrigerant Piping Compliance—OSMC 2014 1107.2.2
Project Information
Building Permit: MEC2016-00068 Construction Type: 5A
Tenant Name: Burnham and Ash Apartments Occupancy Type: M
Address: 12850 SW Ash Occupant Load: NA
Area: NA Stories: 4
Per OMSC 2014 1107.2.2: "Refrigerant piping shall not penetrate floors, ceilings, or roofs."
Exception 4 Exempts"Penetrations by piping in a direct system where the refrigerant quantity does not exceed Table
1103.1 for the smallest occupied space through which the piping passes."
The Smallest Occupied space(s)through which the piping passes is the 3 restrooms in the X25 stack(225, 324,425).This
restroom has been calculated,accounting for sheetrock,to have a volume of 492.4 cubic feet(calculation sketch
attached for reference).
The 4 ton split system in question will be charged to 12.31 lbs of refrigerant(R410a) maximum.
Per OMSC 2014 Table 1103.1,the maximum amount of refrigerant per occupied space for R410a is 25 lbs/1000 cubic
feet.
12.31 Lbs/492.4 cubic ft* 1000 cubic ft/lb allowed=25.
Maintaining a maximum charge of 12.31 lbs of refrigerant in FC/HP 1-1-3 is sufficient to comply with Exception 4 of
OMSC 2014 1107.2.2
Respectfully,
Brian Shea and Mac Nelson
American Heating, Inc.
(503) 239-4600
brian@americanheating.net
mac@americanheating.net
AMERICA N
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