Mezzanine Door GateMezzanine Door Gate Self Closing Mezzanine Safety Gate for Upper Level Door Openings The Mezzanine Door Gate secures openings on upper or mezzanine levels where a standard operating door, single door, double door, or roll up door is used to move supplies, support production, access storage, or provide ventilation. Each gate is custom fabricated to the specific opening. Although hollow metal doors are often standard sizes, the clear opening must be