MEP commissioning
Energized systems testing, pressure testing, arc flash controls, and construction-operations interface during building commissioning.
Mechanical, electrical, and plumbing commissioning is the phase of a building project where everything gets turned on for the first time. Electrical systems are energized. Mechanical systems are tested under pressure. Controls are calibrated. HVAC is balanced and tested and adjusted. It is also the phase where the gap between construction safety and operational safety is most pronounced — and most consequential.
During commissioning, a building is no longer a construction site in the traditional sense. Electrical systems that were de-energized throughout construction are now live. Pressure in piping systems may exceed static values during flushing and testing sequences. Fire suppression comes online in occupied sections. Workers trained to OSHA 1926 construction standards are now working in an environment governed by OSHA 1910 General Industry standards — and that transition is rarely formally marked. Most incidents in commissioning happen because the old habits and assumptions from the construction phase carried forward into an environment that no longer tolerates them.
Greenberg Safety provides commissioning safety support for projects ranging from commercial high-rises and hospitals to data centers and advanced manufacturing facilities. We define safe-work boundaries for each commissioning phase, establish energized work and pressure test permit systems, coordinate between the construction contractor and the operations team, and provide the oversight that prevents 'almost done' mentality from producing the incidents that delay project closeout.
Energized Systems Testing
First energization of electrical systems presents the highest arc flash risk in the project lifecycle. NFPA 70E-compliant work practices, incident energy-rated PPE, and signed energized work permits must be in place before any testing begins — not assembled after the fact.
Pressure Testing
Pneumatic pressure testing of piping systems presents catastrophic failure risk if test pressures are incorrectly set or test boundaries inadequately isolated. Hydrostatic testing is preferred where feasible. Written test procedures with maximum allowable test pressures must be approved before any test begins.
Construction-Operations Interface
Systems handed over to operations during phased commissioning must be formally demarcated. Workers from different crews in the same space need clear spatial and procedural separation — a hard barrier and a permit system, not a conversation.
Confined Spaces Created During Commissioning
Mechanical rooms, plenums, electrical vaults, and equipment pits that become permit-required confined spaces during commissioning may not have been treated as such during rough-in. Atmospheric testing and permit procedures must be re-evaluated at commissioning phase entry.
Chemical Systems Startup
Refrigerant charging, chemical feed system commissioning, and chemical water treatment initialization all involve hazardous materials. Chemical-specific PPE, SDS access, and emergency response procedures must be in place before any chemical is introduced.
Fall Hazards During Equipment Access
Commissioning requires access to rooftop HVAC equipment, elevated mechanical rooms, and ceiling-level AHUs. Fall protection that felt unnecessary during familiar rough-in work is still required — and the familiarity of the space can be the most dangerous part.
- ASHRAE Guideline 0 — The Commissioning Process
- NFPA 70E — Standard for Electrical Safety in the Workplace
- OSHA 29 CFR 1926 — Construction
- OSHA 29 CFR 1910 — General Industry
- ASME B31.3 — Process Piping (pressure testing references)
- ASME B31.1 — Power Piping (pressure testing references)
- NIBS Guideline 3 — Exterior Enclosure Technical Requirements
- OSHA 29 CFR 1910.146 — Permit-Required Confined Spaces