In areas using HVLS fans, where must the fans be located in regards to sprinkler placement?

According to NFPA 13, the placement of High-Volume, Low-Speed (HVLS) fans is critical to ensure they do not negatively impact the performance of the automatic sprinkler system. The standard requires the vertical centerline of the fan to be positioned approximately in the center of a bay formed by four adjacent sprinklers. This specific arrangement minimizes the fan blades' potential to obstruct the spray patterns of any single sprinkler, thereby allowing for the most effective water distribution over a fire should the system activate. This placement considers the fan as both a potential obstruction and a factor in air movement.

B. Centering between two sprinklers would place the fan directly under a branch line, creating a more significant and continuous obstruction than the specified four-sprinkler arrangement.

C. Placing fans as close as possible to sprinklers would create a severe obstruction to the sprinkler's discharge pattern, violating fundamental obstruction rules in NFPA 13.

D. This is incorrect as NFPA 13 provides explicit requirements for the installation of HVLS fans in sprinklered buildings due to their significant impact on fire dynamics.

1. NFPA 13, Standard for the Installation of Sprinkler Systems (2022 Edition).

Section 14.2.12.2.3: "The vertical centerline of the HVLS fan shall be centered approximately between four adjacent sprinklers." This section explicitly states the requirement that directly supports the correct answer.

2. Fire Protection Research Foundation. (2011). Sprinkler Protection for Storage with HVLS Fans (Phase 1).

Page 2, Section 1.1: The report, which provides the technical basis for the NFPA 13 rules, discusses the test setups. It states, "The fans were located with the hub centered in a four-sprinkler array..." This research confirms the principle of centering the fan between four sprinklers to study and mitigate its impact.