B-class Doors with Z-channels: UK26/F001
Adopted EU recommendation FIRE-102. UK approved recommendation UK26/F001 on B-class doors with Z-channels.
Question
B-class doors have been type approved with Z-channels, i.e. ventilation with opening in the lower part on one side and upper part on the opposite side.
Is it acceptable to approve B-class doors with Z channels?
Background
Approvals were originally granted on the basis of successful completion of the Fire Test Procedures (FTP) Code Part 3 tests, with fire exposure from both sides. Under these approvals, B-class division were not required to be smoke-tight, and one of the Z -channel openings was located in the lower part of the door.
Subsequently, these approvals were challenged by a flag administration citing non-compliance with SOLAS Reg. II-2/9.4.1.2.1 and 9.4.2. These provisions specify that when ventilation openings are permitted, they must be located in the lower part of the door.
SOLAS Reg. II-2/9.4.1.2.1: Doors and door frames in “B” class divisions and means of securing them shall provide a method of closure which shall have resistance to fire equivalent to that of the divisions, this being determined in accordance with the Fire Test Procedure Code except that ventilation openings may be permitted in the lower portion of such doors. Where such opening is in or under a door the total net area of any such opening or openings shall not exceed 0.05 m². Alternatively, a non-combustible air balance duct routed between the cabin and the corridor and located below the sanitary unit is permitted where the cross-sectional area of the duct does not exceed 0.05 m². All ventilation openings shall be fitted with a grill made of non-combustible material. Doors shall be non-combustible. Doors approved without the sill being part of the frame, which are installed on or after 1 July 2010, shall be installed such that the gap under the door does not exceed 25 mm.
SOLAS Reg. II-2/9.4.2.3: In corridor bulkheads ventilation openings may be permitted in and under the doors of cabins and public spaces. Ventilation openings are also permitted in “B” class doors leading to lavatories, offices, pantries, lockers and store rooms. Except as permitted below, the openings shall be provided only in the lower half of a door. Where such an opening is in or under a door the total net area of any such opening or openings shall not exceed 0.05 m². Alternatively, a non-combustible air balance duct routed between the cabin and the corridor and located below the sanitary unit is permitted where the cross-sectional area of the duct does not exceed 0.05 m². Ventilation openings, except those under the door, shall be fitted with a grille made of non-combustible material.
The flag administration was informed that the practice of approving B-class doors with Z-channels would be discontinued.
Recommendation
No, Z-channels should not be considered acceptable in B-class doors, as the location of the opening does not meet the regulatory requirement when viewed from one side, and therefore does not comply with SOLAS Reg. II-2/9.4.1.2.1 or 9.4.2.
References:
- MSN 1874 as amended
- The Merchant Shipping (Marine Equipment) Regulations 2025
Items affected:
- UK/3.16, Fire doors
More information
Maritime and Coastguard Agency
Bay 2/21
Spring Place
105 Commercial Road
Southampton
SO15 1EG
Telephone: +44 (0) 203 817 2000
Email: MEQA@mcga.gov.uk
Website: https://www.gov.uk/mca