Arc Flash Suit Hood
An arc flash suit hood is an arc-rated, flame-resistant hood that fully encloses the head, neck, and often part of the shoulders, with an integrated arc-rated face shield. It provides 360° thermal and impact protection from an electric arc flash as part of a complete arc flash suit ensemble, tested under ASTM F2178 for incident energy ratings in cal/cm².
On a manufacturing floor, an arc flash suit hood is mandatory for tasks with incident energy ≥8 cal/cm² (NFPA 70E Category 2 and above), such as opening energized switchgear or working inside MCC buckets. It is worn with arc-rated jacket, pants, gloves, and dielectric footwear. The hood integrates with safety glasses and hard hat underneath, and may include ventilation systems with FR components for extended tasks. WorkSafeBC requires selection per CSA Z462 and ASTM F2178, with documented inspection and maintenance routines.
How is the arc rating of an arc flash suit hood determined and why can it differ from the suit’s rating?
The hood’s arc rating is determined by testing the complete hood system under ASTM F2178, establishing its Arc Thermal Performance Value (ATPV) or ELIM. CSA Z462 notes the hood rating often differs from the suit fabric due to the transparent visor’s thermal behavior and design features like air gaps and hardware. Facility engineers must separately verify the hood’s rating against equipment incident energy labels.
At what point must a worker move from an arc-rated face shield to a full arc flash hood under CSA Z462/NFPA 70E?
Under NFPA 70E PPE categories: Category 1 (4–<8 cal/cm²) allows AR face shield + balaclava; Category 2 (≥8–<25 cal/cm²) requires an arc flash hood (minimum 8 cal/cm²); Category 3 (≥25–<40 cal/cm²) requires a 25 cal/cm² hood; Category 4 (≥40 cal/cm²) requires a 40 cal/cm² hood. Many procedures mandate a hood when incident energy exceeds 8 cal/cm² or when the back of the head is within the arc flash boundary.
Does an arc flash suit hood protect against electrical shock or blast pressure?
No. Arc flash hoods are primarily designed for thermal protection from electric arcs, not shock or concussive pressure. Shock protection requires insulated gloves, tools, and de-energization/LOTO. Blast pressure is mitigated by work practices like distance and remote racking; the hood offers limited mechanical protection from debris.