What You Should Know About IMC and NFPA 96 Codes

Posted by Jenni Fredrickson on 03/22/2019

What You Should Know About IMC and NFPA 96 Codes

We recently had a follower ask us a question on social media that we just couldn't brush off with a simple answer. Shayne asked us "What are the main points of conflict or contradictions between the IMC and NFPA 96 regarding access panels?"


As thought leaders in our industry, we didn't want to give a generic response or brush off his question. Shayne went on to explain that he constantly sees "issues in new construction with complex kitchen exhaust systems where they are built to code (aka IMC), but do not meet the Industry Standards (aka NFPA 96). It's a worthwhile discussion to look at the differences and see how to better align them for safety as well as for your customers' pocketbooks."

You're absolutely right, Shayne. It is a worthwhile discussion and we wanted to make sure that all the information we provide is 100% accurate and considers all sources. Here are the main issues we come across when comparing IMC codes vs. NFPA codes:

  1. NFPA says “Openings shall be provided at the sides or at the top of the duct, whichever is more accessible, and at changes of direction.”  vs. IMC that says that grease ducts shall not have openings except where required for the operation and maintenance of the system.

 

  1. NFPA says that on horizontal ducts, at least one 508 mm × 508 mm (20 in. × 20 in.) opening shall be provided for personnel entry. On vertical ductwork where personnel entry is possible, access shall be provided at the top of the vertical riser to accommodate descent. IMC does not address either of these requirements.

 

  1. NFPA says “(12 ft) intervals. 7.4.1.3 If not easily accessible from a 3 m (10 ft) stepladder, openings on horizontal grease duct systems shall be provided with safe access and a work platform vs. IMC calls for intervals spaced not more than 20 feet (6096 mm) apart and not more than 10 feet (3048 mm) from changes in direction greater than 45 degrees

 

  1. NFPA says that on nonlisted ductwork, the edge of the opening shall be not less than 38.1 mm (11∕2 in.) from all outside edges of the duct or welded seams. IMC mentions nothing about it.

 

  1. NFPA says “Grease Tight” and IMC says “Liquid Tight”

 

  1. NFPA says nothing about needing any signage or label marking to door and IMC says “An approved sign shall be placed on access opening panels with wording as follows: "ACCESS PANEL. DO NOT OBSTRUCT."

  2. NFPA says “On nonlisted ductwork, the edge of the opening shall be not less than 38.1 mm (11∕2 in.) from all outside edges of the duct or welded seams.”VS. IMC mentions nothing about it.

    These are some of the most dynamic comparisons we see but clearly, there are other subtle differences throughout the codes and the language in which they were written.


    Thanks for the question, Shayne! 

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