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4.29.21 – SSI –  Shane Clary 

Shop drawings should not be confused with engineering drawings. Here are the minimum requirements according to NFPA 72

Originally there was to be a different topic covered this month. But after recently viewing how a number of shop drawings were produced the subject is now shop drawings, and what should be the minimum requirements for any set — from the smallest system to a large complex system.

Since the 2013 edition of NFPA 72National Fire Alarm and Signaling Code, there has been a chapter on documentation. This is Chapter 7. Prior to the 2013 edition, the requirement for documentation was located within the chapter on Fundamentals. The Technical Committee on Fundamentals still has oversight for Chapter 7, as documentation is viewed as being a fundamental requirement for all systems.

Shop drawings should not be confused with the engineering drawings. These drawings would be completed and in most cases sealed by a professional engineer. The professional engineer in most cases will either be an electrical engineer or fire protection engineer. In the engineering drawings, the location of the detection devices and notification appliances are laid out.

A sequence of operation as well as the intent and description or narrative of the system would be provided. This information is then taken by the installing contractor and converted into the working drawings or shop drawings. It is these drawings to which the system is installed.

The minimum requirements for the design or layout drawings are found in Section 7.3 of the 2019 edition. The standard states that these are only necessary when required by local laws or regulations. The building owner may also require that a design professional prepare the initial layout.

This would certainly be the case if the system is to be based on a performance design as opposed to prescriptive. It is my opinion that in no case should a contractor be doing a layout of as system based on performance requirements unless they are also a registered design professional qualified for the scope of work that is to be performed.

Within Section 7.3 there is a reference to 10.5.1, which is the minimum qualifications that a system designer should have. As I have stated above, do not confuse the production of shop drawings with design drawings.

Within Chapter 7, there are minimum requirements as to what is to be included within the documentation for the project. These are found within paragraph 7.2.1. They include but are not limited to the following:

  • System description
  • Riser diagram
  • Floorplan
  • Sequence of operation
  • Battery calculations
  • Voltage-drop calculations
  • Mounting heights
  • Location of devices and appliances
  • Wiring details

The requirements for shop drawings are found in Section 7.4. Paragraph 7.4.5 has the minimum requirements. These include but are not limited to:

  • The direction of north
  • Graphic scale
  • All walls and doors
  • All partitions that extend to within 15% of the ceiling height
  • Room descriptions
  • Locations of system devices and appliances
  • Ceiling heights and geometry
  • Location of the primary power source

The list of minimum shop drawing requirements begin with this statement “…Floor plan drawings shall be drawn to an indicated scale and shall include the following information, where applicable for the particular system.” It is the end of the statement that is important to note.

If one is installing a smoke detection system within a building that has unique ceiling geometries, then a side elevation would be warranted. But if the ceiling has been documented as being flat and smooth and at 9 feet above grade, a note to that affect shall suffice.

If the project is to just supervise the building’s fire suppression sprinkler system, the inclusion of ceiling details or even all rooms within the structure may not be required. The scope of the project should dictate the complexity of the shop drawings. Information and details to assist the installer should not be omitted.

The installer of the system needs to note on the shop drawings any deviations that may have been taken so that a set of Record-Set or As-Built drawings can be completed. The minimum requirements for these drawings are to be found in Section 7.5.5.

In my observations, it is rare that the final installation of a system matches the shop drawings. The production of the record drawings is required by 72, and should not be placed on a “backburner.” These tend never to get completed.

A proper set of drawings, from the start to the conclusion well go a long way in assuring that the system is installed correctly and to code, and will eliminate issues that could occur during the installation if this documentation was not present.

In next month’s article, I will cover mass notification systems. In June, we’ll look at a new standard being developed by the NFPA on fuel gasses detection.