Luckett & Farley recently had the privilege to design a sawmill facility for one of our long-standing clients. During its design, we faced a challenge from the state fire marshal’s office (the authority having jurisdiction) regarding the building occupancy classification. The fire marshal had seen some horrible conditions in other sawmills and was strongly leaning towards classifying this building as H-1 (High Hazard) occupancy rather than F-1 (Factory). This could have been a very expensive proposition because of all the explosion-proof electrical devices on all the machinery and explosion-proof lighting required for H-1 occupancy.

So, the lead architect from Luckett & Farley met with the fire marshal to review the operations of the sawmill in detail. He discussed with the fire marshal that the logs are kept wet on site (50%-75% moisture content) and, when cut, the resulting saw dust and shavings (over 50% moisture content) are less combustible.  The plant also has a dust collection system with inlets throughout the facility, but it wasn’t a perfect solution. Cleanup was required several times daily to help prevent accidental ignition.  The fire marshal wanted more proof of the moisture content in the saw dust, especially the saw dust that had escaped the dust collection system and dried over a period of time. He also wanted further detail on the owner’s plan for standing dust prevention, as required by NFPA 664.

Happy to oblige, Luckett & Farley worked with an independent testing agency to obtain samples of the saw dust from the owner’s other sawmill with similar operations. The samples were collected from the floor (1) in the morning after about one hour of operations, (2) early afternoon and (3) end of the day. The moisture content was measured and charted to show the saw dust did maintain significantly high moisture content throughout the day’s operations and remained less susceptible to ignition and combustion.

Luckett & Farley also worked with the owner to prepare a comprehensive package to the fire marshal to demonstrate compliance with the building code, including NFPA 664 containing the following:


  1. Building design minimizing any surfaces for dust collection, which included providing interior metal liner panels on the exterior walls, special profile light fixtures to reduce dust collection, no duct work for heating and ventilation, minimum conduits, etc.
  2. A Building design that included an automatic sprinkler system and fire extinguishers as required by NFPA .
  3. Dust collection system information.
  4. A Detailed daily cleaning program for the removal of the saw dust from the plant floor periodically during the day, end of each day and total plant cleaning quarterly.
  5. Moisture content test results and charts showing the high moisture content in the saw dust.

Upon final review of the documents provided to the fire marshal’s office, they approved the plant for construction based upon our proposed F-1 classification.

It’s a strong example of smart design through creative problem-solving, and it happens every day at Luckett & Farley. Our knowledgeable staff can play a critical role for owners in the code review process, saving time, money, and most of all…worry.  This project is an example of how a proactive approach early in the design phase was able to save the client up front and maintenance costs by avoiding a stringent hazardous occupancy type.  Had this discussion taken place at the permitting stage, the project would have suffered delays and Luckett & Farley may have been unable to address the AHJ’s concerns in a timely fashion to avoid the hazardous occupancy.

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