Why Are Electrical Rooms in Data Centers a Problem?
Electrical rooms in data centers increasingly meet the legal definition of a confined space, even though at first glance many do not look like one. Cable trays, switchgear and UPS installations are rarely located at ground level: access is often through openings at roughly 3.5 to 5.5 meters in height. Under the U.S. construction standard set by workplace safety regulator OSHA (29 CFR 1926.1203), a space is considered a permit-required confined space when it is large enough to enter, has limited means of entry and exit, and is not designed for continuous occupancy. That is what trade publication ISHN points out in an analysis of data center construction practices in California’s Bay Area.
The problem is that two risks coincide. On one hand, work at height: employees reach elevated work areas through narrow access points. On the other hand, confinement: the rooms are compact, with limited entry and exit points and little natural ventilation. Energized switchgear generates heat that cannot escape as long as the room is still under construction and the climate control system is not yet operating. In rooms with backup power systems (UPS), the risk of gas buildup from lead-acid or lithium-ion batteries during charging and testing adds to that. Workers therefore have to contend simultaneously with fall hazards, heat, a potentially hazardous atmosphere and a difficult escape route.
What Measures Are Needed?
According to the analysis, the solution lies not in separate measures for each discipline, but in a single coordinated safety plan that assesses access height and confinement together from the start of construction. Specifically, it recommends reviewing room classifications periodically, tied to major installation milestones such as the installation of cable trays, the placement of switchgear and the UPS going into service, rather than classifying rooms only once at project start. Rescue plans must be based on the actual access points, including their height, so that a rescue does not get stuck at an opening that is too narrow or too high. Before every entry, the atmosphere in the room must be tested with calibrated multi-gas meters, under the supervision of trained personnel who remain outside the space. Finally, it is recommended that a single person be designated to monitor, across all contractors and disciplines, whether a room needs to be reclassified as a confined space.
Regulatory Developments
The urgency is reinforced by new regulation: since January 1, 2026, the U.S. state of California has had an additional requirement (under Title 8) mandating that a qualified person inspect the work area for confined spaces before construction begins and repeat that inspection regularly, so that spaces created during the project are identified in time. That reflects the reality that a construction site changes: an area that is an open workspace at the start of a project can become a confined space once cable trays, equipment and walls are installed. Outside the United States, different legal frameworks apply, but the core message – treating access and confinement as a single risk – is internationally relevant for anyone who builds or maintains electrical rooms in data centers.
Context
Confined spaces are considered especially hazardous work environments. Figures from the U.S. Bureau of Labor Statistics, cited in safety overviews of the federal OSHA standard 29 CFR 1910.146 (Permit-Required Confined Spaces), show an average of about 92 fatal accidents per year in confined spaces over a five-year period around the turn of the century, ranging from 81 (1998) to 100 (2000) per year. Research by the U.S. institute NIOSH into 217 deaths found that hydrogen sulfide and carbon monoxide were the most common gases involved. NIOSH also estimates that around sixty percent of victims were rescuers who entered the space to help an earlier victim, underscoring the importance of pre-planned, realistic rescue procedures rather than improvisation on site.
Source: Confined Spaces Create Challenges in Data Center Electrical Rooms, October 5, 2026
Additional research: figures from the U.S. Bureau of Labor Statistics and NIOSH on fatal accidents in confined spaces, in the context of OSHA standard 29 CFR 1910.146.
