Accessory Dwelling Units (ADUs) are a common way for Boston-area property owners to create additional housing—often by finishing existing unfinished space like a basement or attic. From a fire/life-safety standpoint, these projects are less about “ADU” as a label and more about what the building becomes after the work: a single-family with an internal ADU, a two-family becoming three units, or a three-family becoming four units. This article focuses only on ADUs created by co

Adding or modifying warehouse racking is more than a space-planning decision—it can change how a building performs from a structural, fire protection, and life safety standpoint. Because racking can affect sprinkler effectiveness, egress paths, and even lighting conditions, many jurisdictions require a racking permit (often coordinated with a high-piled storage review) before racks are installed and the space is stocked. A well-prepared submittal package is the best way to av

Indoor playgrounds are dynamic, high-activity environments where children move quickly through tight spaces, tunnels, and multi-level play structures. That reality often conflicts with prescriptive sprinkler requirements that were never written with these occupancies in mind. In a recent 12,000-sf indoor children’s playground project in Boston, Engineering Fire Protection (EFP) evaluated whether fire sprinklers should be installed inside multi-level play structures—beneath pl

Automatic Storage and Retrieval Systems (ASRS) represent a fundamentally different fire protection challenge than conventional pallet rack storage. Their dense storage arrangement, narrow aisles, unique rack geometry, and automated operation create fire dynamics that are not addressed by the prescriptive sprinkler design criteria contained in NFPA 13. Importantly, the storage protection rules in NFPA 13 were developed based on full-scale fire testing of conventional rack conf

Two standards define the foundation of Battery Energy Storage System (BESS) fire protection today: UL 9540A, which provides test data, and NFPA 855, which defines how that data is applied. Yet, one of the most persistent challenges for engineers, code officials, and developers is translating UL 9540A test results into NFPA 855–compliant designs. Many submittals fail not due to poor engineering, but because the connection between test data and actual system configuration is un

Explosion control has emerged as one of the most critical and least understood aspects of Battery Energy Storage System (BESS) design. While most fire protection discussions focus on preventing or managing thermal runaway, the secondary hazard—deflagration—often poses the greatest risk to system integrity, first responders, and adjacent equipment. As lithium-ion batteries release flammable gases under failure conditions, these gases can ignite rapidly, producing violent press

The 2026 edition of NFPA 855: Standard for the Installation of Stationary Energy Storage Systems has now been released, continuing the rapid evolution of safety requirements for battery energy storage systems (BESS). Since the first edition in 2020, each cycle has refined how the standard addresses emerging chemistries, larger system capacities, and lessons learned from real-world incidents. For project teams, this edition is more than a simple “tune-up.” It broadens which te

Designing a fire suppression strategy for a Battery Energy Storage System (BESS) is one of the most debated aspects of modern energy safety engineering. Unlike typical industrial or electrical fires, lithium-ion battery fires behave unpredictably and can be extremely difficult—sometimes impossible—to extinguish once thermal runaway begins. As a result, designers and authorities are increasingly rethinking traditional suppression methods. In many cases, the most effective and

As Battery Energy Storage Systems (BESS) become a critical part of renewable energy infrastructure, designers and project teams are learning that fire protection for these systems involves challenges not typically seen in conventional electrical or industrial facilities. While the industry continues to mature, recurring mistakes in the design, permitting, and installation process can lead to costly delays — or worse, create gaps in safety. Understanding these common pitfalls