One of the key objectives of the NIA’s Metal Building Laminator (MBL) Committee is to develop technical and professional guidelines that will help laminators deliver the highest quality products and services, and to promote these standards within the metal building industry, in conjunction with the North American Insulation Manufacturers Association and other relevant organizations. In adhering to that objective, the MBL Committee decided that the existing NIA-Certified Faced Insulation Standard (Standard) for metal building insulation needed to be reviewed and updated.

This is a question that gets asked very frequently, and in most cases, the next question is, “Does the insulation need to be replaced?” The most common response to the original and follow up question is, “It depends”. So, we are going to take you through how insulation typically becomes wet on a job site, what to do if/when it becomes wet, and what preventative measures should be taken to reduce the chance of the insulation becoming wet.

Not all insulation materials are the same. There are various reasons to use insulation, ranging from keeping cool spaces cool or keeping warm spaces warm, to keeping noise in or keeping noise out, or for fire protection, etc. The best advice we can give is to first understand what you need to insulate (type of building), and more importantly, why you need to insulate it (occupied versus storage versus heated versus semi-conditioned, etc.). For the purposes of this article, we will be focused on fiberglass metal building insulation.

A vapor retarder is a material designed to limit the amount of moisture in the air from traveling through it. The effectiveness of a vapor retarder is measured in terms of the permeance of the material. The Permeance is defined as the rate of water vapor transmission through a material in a given amount of time per unit area. Most of us in the industry know this as the “perm” rating. The lower the perm rating, the less moisture that is allowed to pass through the material. The 2015 International Building Code identifies three classes of vapor retarders per ASTM E96 as:

  • Class I: 0.1 perm or less
  • Class II: greater than 0.1 per to less than or equal to 1.0 perm
  • Class III: greater than 1.0 perm to less than or equal to 10 perm

With the exception of Plain Vinyl (Class II), the vast majority of facings used within the Metal Building Industry have a perm rating of less than 0.1 (Class I).

Per the National Building Code – 2019 Alberta Edition Volume 1, Section Defined Terms, a Vapour barrier means the elements installed to control the diffusion of water vapour.

The January 2019 issue of Insulation Outlook featured an article by Dwayne Sloan, Director of Principal Engineers and Regulatory Services for the Building and Life Safety Technologies Division at Underwriters Laboratories (UL), entitled A Focus on Insulation Surface-Burning Characteristics . Within that article, Mr. Sloan referenced model codes and installation standards for insulation products. In this article, we will take a deeper dive into those codes, regulations and requirements as they pertain to insulation for metal buildings.