BEST-LAID PLANS: Five Common Mistakes that Could Get Your Sprinkler Plan Rejected

BEST-LAID PLANS: Five Common Mistakes that Could Get Your Sprinkler Plan Rejected

The proper design and review of fire sprinkler systems takes months or years to learn. "These are very involved systems installed for the safety of buildings and people," said Vince Konwent, an instructor with the Building and Fire Code Academy, in Hoffman Estates, IL.

Konwent has more than 18 years of experience in the fire protection industry, specifically focusing on municipal consulting for the last 13 years. As a professional who performs sprinkler reviews and inspections on a daily basis, he has noticed that there are five common problems he sees most often:

1. Improper Design Classification or Labeling

Occupancy and commodity classification definitions are found in Chapter Two of NFPA-13, but some designers depend too heavily on the examples provided in the appendix.

"For instance, a designer may classify a retail facility with storage as an ordinary hazard facility," said Konwent, "but when the storage exceeds 12 feet in height it would be considered more of a storage facility. So Lowes, Home Depot, your Sam's Club - any store in which items are stacked more than 12 feet high - have to meet a different set of requirements."

Konwent added that properly labeling the plans is also paramount. "It would be impossible to determine the design criteria for a facility if the plans simply state the building is a warehouse facility," he said, "but we frequently see plans that say just that."

2. Missing or Inaccurate Water Flow Test Data

The drawings and hydraulic calculations must include the site of the flow test, and the date and time the test was conducted. The calculations must be taken to the point of the water flow test, not some fictitious or convenient point.

"You can't use some fictitious footage," said Konwent. "You can't put 100 feet in your calculations when the flow test was actually taken 500 feet from the building."

3. Installing the Wrong Sprinklers

It is important that the exact sprinkler indicated on the plans and hydraulic calculations is the sprinkler installed on the job site. There are numerous sprinklers available, each with a unique set of design criteria, flow pressure requirements, spacing requirements and specific obstruction rules. Installing the wrong sprinkler invalidates all the calculations and could put the building and its people at risk.

4. Inaccurate Hydraulic Calculations

"There are several areas in which mistakes can be made while performing a hydraulic calculation," said Konwent. "You have all the pipe lengths, pipe sizes, elevation changes, fittings, and set pressure losses (such as backflow prevention devices) that must be included in the calculations. There are many inputs - any of which could adversely affect a system."

5. Missing Design Documents

Chapter 8 of NFPA 13 lists approximately 44 items that must be indicated on your plans. If one of these items is neglected or missing, it may cause a number of issues that would have to be corrected later in the field. It is far more economical to find and correct these issues early in the design process.