Policy Advisory

Policy Advisory Board Policies and Guidelines (Sheet Metal Workers)

Date: 12/11/2017
Referenced Sources: Division of Professional Licensure

Table of Contents

Board CORI Policy

Code Advisory - Commercial Kitchen Grease Duct Testing

Objective: To provide instructions and requirements for commercial kitchen grease duct testing and inspection, to ensure that the system was installed liquid-tight and grease-tight in order to contain the spread of any grease duct fires, which risk the loss of life and property.

Summary: Currently, many installers and inspectors use the 100-watt light bulb test required by the International Mechanical Code (IMC) to help identify inferior welded seams. This test is not practical for testing field-welded grease ducts vertically installed in shafts where full visibility of all welded seams may not be available, or where a 100-watt light bulb cannot be pushed or pulled through a horizontal duct run.

Effective IMMEDIATELY, the Board advises that the entire grease duct system be leak tested under negative pressure equal to the duct fabrication pressure class. This test will measure and prove the tightness of the duct system without visibly inspecting each welded seam. Instructions on how the test should be performed follow below. State Sheet Metal Inspectors have found this to be effective in identifying leaks that may otherwise not have been visible with a light bulb test.

This test must be performed by a properly licensed sheet metal business or individual that specializes in Testing, Adjusting, and Air Balancing of HVAC systems.

If you have any questions, please contact the Board at 617-727-3022.

Code Advisory - Fire Dampers and Combination Fire/Smoke Dampers

Objective: To provide clear installation instructions and requirements for the installation of standard fire dampers and combination fire/smoke dampers, so that they are installed with adequate access, retaining angles, and clearances for expansion. Adherence to these requirements will allow for proper operation upon activation.

Summary: Ducts with fire dampers and/or combination fire/smoke dampers are often installed incorrectly. Some installers do not provide adequate room for expansion, and the clearance space is sometimes filled with mineral wool, ceramic fiber, or fire-stopping caulks, which is technically unnecessary, potentially detrimental to the installation, and could result in voiding the UL listing of the damper. Where ducts without fire dampers penetrate walls and floors, it is likewise common for the annular space around the duct to be sealed or fire-caulked, which should not be done with fire dampers or combination fire/smoke dampers. 

State Sheet Metal Inspectors have identified the following common incorrect damper installations: 

1) Dampers installed without retaining angles;

2) Dampers installed with retaining angles attached to the duct and sealed to the wall with fire caulk that may limit expansion;

3) Dampers installed without any room for expansion; and

4) Dampers installed with additional material added to the expansion space. 

In order to address these safety concerns, effectively IMMEDIATELY, all sheet metal licensees and inspectors should follow this advisory for the proper and safe installation of fire dampers and combination fire/smoke dampers. More specific instructions follow below.

If you have any questions, please contact the Board at 617-727-3022. 

Commercial / Industrial Metal Watershed Roofing System - Definition

Any flat seam, flat locked and/or soldered seam, standing seam, batten seam, horizontal seam, custom designed or prefabricated metal roofing and related components (flashing, trim, gutters, downspouts, conductor heads and scuppers) that are interconnected to the metal roofing system with mechanical fasteners or locks and seams and are installed on projects that are deemed non-residential per 271 CMR.


Residential buildings as defined in 271 CMR

Through wall flashing

Gravel stops


Soffits and fascia

Gutters and downspouts that are not interconnected and fastened to the metal roofing system

Residential Bathroom Exhaust Fans / Kitchen Exhaust Fans - Interpretation

Residential Bathroom Exhaust Fans / Kitchen Exhaust Fans - Interpretation:

All residential fans and associated ductwork shall be installed by a licensed sheet metal worker.

New installations shall require a sheet metal permit and inspection.

The replacement of an existing residential fan shall be considered a minor alteration and will not require a sheet metal permit.


The installation of combination fan/light units may be installed by a licensed electrician.

Referenced Sources: