Smacna Seismic Restraint Manual

The use of components not precisely identical to these is acceptable. The first step in determining construction requirements is to locate the table with the applicable static pressure. Thermally activated types use heat to either shrink-fit closures or to expand compounds within joint systems. Black iron stiffeners are standard.

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Unfortunately, cross breaking results in concave areas between the break lines. Several alternative constructions are illustrated. Where they are used, the diameter of the branch shall not exceed two-thirds of the diameter of the main and protrusions into the interior of the main, are not allowed. They shall be installed as required to maintain alignment.

If a contractor wants to fabricate this type of casing, it is suggested that strength of the panels be determined by structural calculations or pressure tests on mock-ups. Round duct wall thicknesses in these standards are generally acceptable for below-grade installation.


This introduction does not review all aspects of construction. Construction methods that economically achieve the predicted and desired performance must be determined. Non-Members click here to purchase.

This installation standard is applicable to ducts placed in or beneath concrete floors or in areas free from vehicle traffic. In actuality, the relationship between surface vibration and sound radiation is also a function of frequency. However, other limits may be acceptable if they can be shown to result in equivalent construction. The current test program did not include vibration analysis.

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Category listings are not intented to preclude different selections for fittings that function as area change, direction change, converging flow, diverging flow, or special purpose. Also provides relevant information regarding construction of these architectural elements, the purpose of each, as well as what to look for during periodic inspections. The process works effectively for projects both large and small, simple as well as complex.

Small differences occur in the diameter of ducts and fittings. The options are provided to correlate performance with economy and the preference of fabricators and specifiers. Certain qualitative judgments were made concerning these listening tests. Pipe penetrations shall be sealed to prevent air leakage and condensation movement through the seal.

Fasteners that penetrate the duct may be sheet metal screws, blind rivets, or self-tapping metal screws. Round spiral seam ducts with thinner than traditional wall thickness and with one or more corrugations ribs formed between the lock seams have been introduced in industry.

The test results showed that the effect of cross breaking high velocity ducts is dependent on the sheet gage. Mating flanges are formed on the ends of the duct in double flange style to create a tee shape when assembled. Proper clearances are necessary. Applies to commercial, industrial and residential buildings.

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The first pour should be the base support for the duct and anchors should be included. Separate chapters are devoted to the different levels of commissioning, including basic, comprehensive and critical system commissioning. If the diameter of a round tap is greater than the height of the flat oval body, a transition can be made from flat oval to round, providing an equivalent area at the base of the transition.

Damage to the mechanical systems could mean that a building might be uninhabitable for weeks or months. Some types of flexible duct have received listings as components of fan unit or air terminal unit systems, and they may be governed independently by the conditions of those listings.

The greater duct dimension must be on the top, not on the side. Access to joints for makeup and orientation in vertical or horizontal positions will influence the choice of connection. Construction of aluminum duct and fittings shall otherwise correspond in the same relationship as for steel duct. Why would a light gage sheet resist vibration more than a heavy gage sheet, and why would a sheet vibrate more at lower pressures? The basis of interpretation of the readings of relative vibration is the assumption that the intensity of radiated sound will vary with the intensity of vibration.

SMACNA-Seismic-Restraint-Manual.pdf - SMACNA Seismic

Some appliances are rated for a zero clearance to combustible material. However, because California has such severe, frequent earthquakes, its standards may be too strict for other parts of the country. After the test runs, the consultants listened to the recordings in a quiet room and judged them.

In considering such requests, the Association will not review or judge products or components as being in compliance with the document or publication. The laboratory may just report its findings or may certify that compliance with a particular standard or requirement has been met. The reinforcement spacing in Tables to denotes distance between two joints or two intermediate reinforcements or from a joint to an intermediate member.

In order to accommodate a variety of conditions, these guidelines are somewhat more complicated than the original manual. Then, for about a year, the manual was developed by the task force and consulting engineers, with input from a broad spectrum of users in the sheet metal and plumbing industries. The construction described in this manual is related to heating, cooling, ventilating, and air conditioning systems.

Hangers in contact with the duct shall be galvanized steel or aluminum. Substitutions based on sponsor demonstrated adequacy and approval of the regulating authority are recognized. Contractors will find this book a valuable resource to provide owners or facility managers along with the standard building completion documents. The installation must not develop noise or vibration.

Also contains information on active and passive smoke control systems and smoke detectors, plus soft metrics. Ribbed forms of round duct are not yet standardized, but may be considered under equivalent-performance-alternative provisions. Durable materials such as soft elastomer butyl or extruded forms of sealants should be used in flanged joints.

Lock forming grades of such material must be used. In fulfilling the function of moving air, the duct assembly must satisfy certain fundamental performance criteria.

In cases where there are no integral hangers at the required hanging points, install the rod or strap hangers before concrete placement, or install welded studsafter concrete placement. All transversely oriented edges of liner not receiving metal nosing shall be coated with adhesive.

SMACNA-Seismic-Restraint-Manual.pdf - SMACNA Seismic

As a result, microsoft office 2010 mac full version seismic concerns now include restraints for ductwork and piping in buildings. This manual also does not cover the seismic restraints for fire sprinklers and equipment. The supports discussed here are not seismicly qualified. It now takes more than a simple cookbook procedure to determine the proper restraints.

SMACNA Seismic Restraint Manual 3rd Edition Builder s Book ore