Provide Fire Access for Narrow Mechanical Yard?

7/18/2022

Hoping to gain some insight from industry here:

Working on preliminary layouts for a large industrial facility that is comprised of tilt-up precast single-story building (~40' tall) and flanked on one side by an equipment yard (think generators, switchgears, mechanical equipment) configured in two levels (think mezzanine).

Question is on fire access to the main building: The mechanical yard runs the entire length of the main building and we are considering fire access as the depth of the equipment yard is ~100ft with a limited service corridor separating the two (~12ft) for maintenance and building egress. There will be periodic gaps (~6ft wide) between equipment located at grade, however the access will require passing through the yard on foot (underneath the second level of equipment on the mezzanine) to gain access to the main building.

Per IFC 503.1.1 our fire access roads must provide continuous access to the exterior within 150ft of the building.

Would passing "through" the mechanical yard at grade meet this requirement?

Would placing "driveways" through the yard to allow a truck to pull closer to the building (but being parked underneath the second level) be kosher?

A similar question exists regarding having hydrants located directly under the second level near the extents of the yard, is this OK?

Have been unsuccessful at locating any code references regarding fire access through a "tunnel" if you would. An AHJ perspective would be much appreciated, along with any other thoughts/feedback.

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2 Comments

Greg

7/18/2022 08:25:00 am

One of the first items to consider about fire department access is "why does a fire department want access". Generally, access is for ease of entry into a building or as a defensive posture. The mention of "tip up" wall construction immediately brings to mind limited openings and therefore limited opportunities for entry or defense. In consideration for entry, one must also consider the defensive action of retreat and the ability to move from the building. If I recall correctly, some highly protective risk insurers and government agencies require PIV valves to be located at least 40 ft from exterior walls. Why, you ask? When defensive fire fighting prevails, wall collapse is a distinct possibility. Having the ability to isolate a system, post collapse, will preserve water for large hose streams (when the sprinkler system has failed).

So in describing offense and considerations for defensive firefighting, is there any advantage to accessing the lane described in the question? Looking at the question from a 50/50 chance perspective, yes or no, if there is not a benefit gained for access (offensive and defensive) then the decision should be No.

In deciding that access is not available on one side of the structure, how can the remaining sides be improved upon. Signage, wayfinding and pre-planning are the least expensive, low cost capital items. Roadway improvement, fire zones painting, and additional fire hydrants are higher capital items.

In concluding, consider AHJ input and local fire agency practice. Explain the complexities of 100 percent exterior access and discuss the value of 75 percent (three sides) or alternative means to improve the accessible areas. Discuss and ask questions about primary entry points, personnel doors, roll-up doors (dock doors), secondary entry points, and combustible loading expectations. Improvements could include fire alarm, smoke detection addition, or smoke evacuation system. This may or may not be needed as alternative means but thinking through all of the low to high cost capital solutions is important ahead of your first conversation with the AHJ, or fire response agency.

Todd E Wyatt

7/18/2022 08:51:38 am

The adopted Code for this project (e.g. 2021 IBC?) will define what this "yard" as one of the following :

COURT. An open, uncovered space, unobstructed to the sky, bounded on three or more sides by exterior building walls or other enclosing devices.

YARD. An open space, other than a court, unobstructed from the ground to the sky, except where specifically provided by this code, on the lot on which a building is situated.

EGRESS COURT. A court or yard which provides access to a public way for one or more exits.

I recommend review of the building's Means of Egress (MOE) as access through this "COURT" may be required. IBC Ch 10 Section 1029 Egress Courts includes additional requirements.

For the "second level of equipment", you may want to define these as "EQUIPMENT PLATFORMS" (see IBC Ch 5 Section 505) :

EQUIPMENT PLATFORM. An unoccupied, elevated platform used exclusively for mechanical systems or industrial process equipment, including the associated elevated walkways, stairways, alternating tread devices and ladders necessary to access the platform (see Section 505.3).

Once you have defined this "open, unenclosed space" and the associated "equipment platforms", you can direct your MOE and Fire Protection questions to the AHJs.

Provide Fire Access for Narrow Mechanical Yard?

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