What do you hang ductwork with?

There are three choices of metal ductwork hangers that are commonly used: a polypropylene strap, a metal strap that’s perforated and therefor adjustable, and wire. The polypropylene strap is best in that it can be cut to any length and will not bend or deform the metal ductwork in any way.

How do you support a rectangular ductwork?

Supports for rectangular ducts shall be installed on two opposite sides of each duct and shall be riveted, bolted, or metal screwed to each side of the duct at intervals specified.

Is standard for ducting?

This standard covers materials and constructional requirements of air ducts used for air conditioning and ventilation system (including gas exhausting system). The standards listed at Annex A contain provisions, which through reference in this text, constitute provisions of this stidard.

What are the duct pressure classes as per Smacna?

SMACNA breaks down the sealing of commercial ductwork into three classes: A, B, and C. Class A applies to static pressure of 4″ wg or more and requires all transverse joints, longitudinal seams and duct wall penetrations to be sealed.

How do you support ducts?

If ducts are to be installed in a vented, uninsulated attic or crawl space, hang the ducts with supporting straps or saddles of sufficient width and frequency to adequately support the ducts so that the ducts do not sag and are not pinched or compressed in a manner that would cause damage to the ducts, the duct …

What is Smacna standard?

SMACNA standards help contractors reduce costs, anticipate technical requirements, and increase productivity and efficiency. SMACNA standards and manuals address all facets of the sheet metal industry, from duct construction and installation to air pollution control, energy recovery, and roofing.

How do you measure insulated ducts?

Measure the diameter of the duct then divide it by 2 to get the radius. Square the radius then multiply the radius by Pi, or 3.14. This will give you square inches of the duct. Divide that total by 144 to get square feet of the actual duct.

What is duct pressure classification?

Duct systems are often divided into three pressure classifications: High Pressure Systems – where fan static pressures are in the range 6 to 10 in WC (1500 – 2500 Pa) and duct velocities in general less than 4000 fpm (20 m/s)

What is the classification of duct?

There are three types of duct systems. Namely, flexible ductwork, rigid ductwork, and semi-rigid ductwork. We’ve compiled information on each of these duct systems. These ducts are typically tube-shaped and made of a wire coil covered with a bendable, durable plastic, and surrounded by insulation.

What are the standards for duct work in HVAC?

If the designer does not designate pressure class for duct construction on the contract drawings, the basis of compliance with the SMACNA HVAC Duct Construction Standards is as follows: 2” (500 Pa) w.g. for all ducts between the supply fan and variable volume control boxes and 1” (250 Pa) w.g. for all other ducts of any application.

What are the subjects of the ribbed round duct study?

Subjects being investigated are ribbed round duct, fatique testing of tie rodded metal, new flat oval duct standards, duct liner pin lengths, more double wall casings, sealant specifications and more performance specifications for joints and reinforcements.

What are the basic elements of duct construction?

The basic elements of duct construction consist of duct wall(s), transverse joints, and reinforcements at, or between, joints and supports. All of these form an integrated combination for each pressure class and duct size. Each size in a pressure class has a minimum duct wall thickness and a minimum specification for joints, reinforcements, etc.

How big are the joints on a HVAC duct?

The duct will be 18 gage. The joints will be TDC/TDF. The joint length is 56 inches. The 140 inch side will be supported by 1” EMT conduit spaced 46 5/8” across the width and will be at each side of the joint and backing up the mid-panel reinforcement.