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Mandatory Window Inspection Scheme

Scope and standards



Under the Mandatory Window Inspection Scheme (MWIS), owners of buildings aged 10 years or above (except domestic buildings not exceeding 3 storeys) and served with statutory notices are required to appoint a Qualified Person (QP) to carry out the prescribed inspection and supervise the prescribed repair works found necessary of all windows of the building. Where a prescribed repair is required, the owners concerned must appoint a registered contractor to carry out the prescribed repair under the supervision of a QP.

Scope and Standard of Inspection and Repair

Window Inspection

Under the MWIS, the inspection shall cover all windows and glass louvers in individual premises and common parts of the building including window walls. Internal glass partitions and shopfront show windows on ground floor are not windows within the scope of prescribed inspection under the MWIS, and curtain walls are covered by the MBIS and not the MWIS.

The QP should adopt the design standard and code of practice prevailing at the time when the building was constructed and when alteration and addition works were carried out, and the standard achieved after completion of the improvement works resulting from the implementation of the Fire Safety (Commercial Premises) Ordinance (FS(CP)O) or Fire Safety (Buildings) Ordinance (FS(B)O) as the inspection standard.

All windows within common parts of the buildings
Glass louvers
Windows at common staircase

The Qualified Person must carry out the prescribed inspection personally to ascertain whether the windows have been rendered dangerous or are liable to become dangerous.

Areas for Attention in Inspection and Assessment

  1. Glass panes:
    • broken or cracked
  2. Window frames and sashes:
    • difficult to open or in jerky motion
    • deformed or cannot be secured
  3. Hinges:
    • deformed or missing parts
    • seriously corroded
  4. Rivets and screws
    • loosened or missing
    • greyish white powder or rust

Points to note:

Under the MWIS, all defective window components affecting window safety must be repaired or replaced. As for those window components not affecting safety e.g. weather sealant, weather gasket/strip, etc., they are not within the scope of prescribed inspection and repair under the MWIS. If the ageing of window gaskets affects the smooth operation of windows or even results in water leakage, the QP may advise the owner to have defective non-structural window components repaired in conjunction with the window repair. In this regard, the QP should advise the owner which items of repair are safety-related and therefore must be carried out under the MWIS and which are recommended repair items.

Window Repair

If repair is found necessary after the inspection, the performance of the rectification and repair works shall NOT be inferior to that required by the regulations, standards and codes of practice prevailing at the time when the building was constructed and when alteration and addition works were carried out, or if fire safety improvement works had been completed in accordance with the Fire Safety Directions issued under the FS(CP)O or FS(B)O, the standard of such completed works.

The Code of Practice for the Mandatory Building Inspection Scheme (MBIS) and the Mandatory Window Inspection Scheme (MWIS) 2012 (2023 Edition) (CoP) issued by the BD has stipulated in details the required scope, methods and standards on inspection, the categories of building damages and the required repair, etc.

Examples of defective window components

Broken and cracked glass panes
Bent or loose bar hinges
Rusted screws

Audit Checks

The BD will conduct audit checks on the inspection reports and certificates in the specified forms submitted by the QPs in order to ascertain that the inspections and repairs have been carried out in accordance with the regulation and the guidelines issued by the BD.

If irregularities of the service providers (i.e. QP and RC) are found, the BD will consider instigating prosecution and/or disciplinary actions against them.

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