What Is An Engineering Judgment?

Overview of Engineering Judgments

What is an EJ? 

An engineering judgment, or EJ as they are commonly known, is a drawing or group of drawings typically generated by a firestop manufacturer for a customer’s jobsite-specific application. They are recommended as a solution when a customer’s jobsite condition deviates from a tested firestop design/system. 

What is their purpose? 

Contractors consistently encounter unique jobsite conditions requiring new penetrations through fire-rated assemblies regardless of how many firestop systems are tested and approved by third-party testing agencies. Custom drawings are sometimes needed in order to provide the most comprehensive fire protection solution for an entire project to account for these unique applications for which a tested and approved system does not already exist. 

How are these drawings created? 

Per International Firestop Counsel (IFC) guidelines, engineering judgments are firestop designs created by qualified personnel based off of third-party tested and approved systems. These designs are in accordance with the recommended IFC guidelines for evaluating firestop system engineering judgments.

Engineering Judgments at Hilti 

Firestop systems are designed and installed to impede the passage of fire, and toxic smoke, with some systems designed to also restrict water and sound, through construction openings in fire-rated assemblies. These systems are required by all Model Building Codes to be tested and rated as part of an assembly in accordance with ASTM E-814, ASTM E-1966, ASTM E-2307, or CAN/cUL 8115 and/or other applicable fire testing standards (UL 1479/UL 2079). The International Building Code (IBC) justifies the use of engineering judgments as referenced under sections 703.2 Fire Resistance Ratings and 703.3 Alternative Methods for Determining Fire Resistance, IBC 2012. The testing and rating process ensures that each specifically designed system will maintain or exceed the hourly fire rating, as tested, for which it was approved.

The IFC guidelines recommend that tested systems be used in lieu of engineering judgments when available and that engineering judgments be based on previously tested systems. Additionally, engineering judgments should only be issued by qualified technical personnel.

All project and application-specific information, such as the penetration type and size as well as the location of the penetrating item, must appear on the drawing. Engineering judgments must only be issued for a single job and should not be transferred to another job without review by the entity who issued the EJ of all aspects of that job’s specifications to determine whether or not the EJs are applicable to the new project. 

Highlights of the IFC Guidelines for Evaluating Engineering Judgments

Key Fundamental Guidelines 

  • Use tested systems in lieu of EJs when available 
  • Issued only by qualified technical personnel 
  • Based upon interpolations of previously tested firestop systems and are referenced on the form 
  • Based on the expectation that the recommended firestop system will perform as designed if subjected to the appropriate firestop test standard for the required fire-rated time period 
  • Limited only to the specific conditions upon which it was rendered 
  • Issued for a single job and are not transferable to another job without review by the entity who issued the EJ of all aspects of that job’s specifications to determine whether or not the EJs are applicable to the new project 
  • Issued only in those locales where local code enforcement jurisdictions permit their use as suitable for meeting building code requirements 

Basic EJ Presentation Requirements 

  • Present in descriptive formal written form with or without detail drawings
  • Indicate clearly that the recommended firestop system is an Engineering Judgement and NOT a listed system • Identify job, contractor, non-standard conditions and required hourly rating
  • Provide complete descriptions of all vital elements of the firestop system (i.e. type of assembly being penetrated, type of penetrant, size of opening, annular space requirements, etc.) 
  • Include clear installation instructions for the firestop system
  • Show dates of issue and authorization signatures as well as issuer’s name, address and telephone number 
  • Reference the number of the tested system(s) the design is based on 

Three Steps to Requesting an Engineering Judgment

  1. Gather all required project and application information. 
  2. Download an Engineering Judgment Request Form. Fill out the required fields marked with an asterisk (*). Accurate information helps expedite your request. 
  3. Email the completed form here. Please also include a sketch of your firestop application along with your Engineering Judgment Request Form. A member of our Firestop Team will be in touch regarding your EJ request.


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