13 to 51mm tough airstream surface resists shop installation and service damage sheet metal ducts must be tightly sealed fibrous glass duct liners are manufactured to.
Ductwork installation guide pdf.
Duct pieces equivalent length x number used equivalent length wall cap 40 ft.
Ducts conforming to nfpa 90a or 90b shall meet the following requirements.
Sheet metal duct lined with fibrous glass insulation duct liner secured to sheet metal with adhesives plus metal fasteners available in thicknesses from 1 2 to 2 in.
Design documents œ instructions to the contractor œ insuring that the design documents convey to the hvac contractor what the designer wants by clarifying features shown on the drawings and described in the schedules and specifications.
The following duct sizes are based on a fraction drop of 10 inches per 100 feet of lineal duct.
The following chart describes an example of one possible ductwork installation.
Larger volumes or higher static pressures should be dealt with on an individual job basis.
Installation instructions a manufacturers printed instructions in accordance with the terms of their listing which advises the method and materials to install the flexible duct.
Shall be tested in accordance with sections.
Fabricate ductwork with 1 fl ange out on top opening and with an outside dimension that is smaller than inside dimension of duct openings cre ated by duct support system.
Leakage the time rate of air volume loss expressed in cubic feet per minute cfm l s.
Designers working alone are.
Checking the work œ quality control œ chapter 12.
Instructions install duct support system in leveled and squared curb.
This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications.
Ductwork is to be furnished by the contractor and is not included with the.
X 2 20 ft.
A common duct pressure of 0 25 inches water column is equal to 0 25 divided by 27 7 in wc psi 0 009.
For installing in high ambient temperatures above 90 f consult aqc industries for special installation instructions.
Duct system design guide first edition 2003 mcgill airflow corporation mcgill airflow corporation one mission park groveport ohio 43125 duct system design i.
Contractors and specifiers who design and install duct systems although there is an abundance of published literature concerning mechanical.
1 psi equals 27 7 inches of water gauge.
For best results and ease of installation store the clamps gaskets and caulk at between 50 and 80 f.
Equivalent lengths of duct pieces are based on actual tests.
Installation requirements 4 1 code reference the authority having jurisdiction should be referenced to determine what law ordinance or code shall apply in the use of flexible duct.
90 elbow 10 ft.
Ordinary heating ventilating and air conditioning duct systems read air pressures at 0 4 psi or less often much less.
X 1 40 ft.
Site condition and preparation it is not prudent practice to install underground duct work where ground water is present.