Author Archives: builderblog2020

Code of Practice for Demolition of Buildings – Bamboo Scaffold

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  • Bamboo Scaffold

The requirements of the Code of Practice for Bamboo Scaffolding Safety have to be complied with.

In addition, structural ties to the building structure shall be provided in accordance with manufacturer’s recommendations. Bamboo scaffold shall be tied to sound anchors at intervals of not more than 4m in both horizontal and vertical directions.

If the scaffold is higher than 15m, steel brackets anchored to the existing building structure or other support system shall be provided at interval of not more than 15m to support the scaffold.

Code of Practice for Demolition of Buildings – Scaffolding Construction and Work Platform Requirements

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  • Scaffolding Construction and Work Platform Requirements

The erection, dismantling and safety requirements of the work platforms and scaffold shall be in accordance with the Construction Sites (Safety) Regulations and the relevant codes of practice on scaffolding safety issued by the Labour Department. The works shall be carried out by trained workmen under the immediate supervision of a competent person.

Supports for the scaffolds should be of adequate strength to hold the vertical and lateral loads imposed on the scaffolds including the catchfans, work platforms, etc. In case when elevated supports are required to receive the weights of the scaffolds, be they the steel brackets and anchors fixed to the existing building or other kinds of supporting system, they shall be designed by a Registered Structural Engineer. Where working platforms are required to facilitate working at height, they shall be properly constructed and provided on the three consecutive lifts directly below the floor being demolished with toe boards provided at the outer edge. Periodic maintenance shall be performed to remove any debris accidentally falling out of the building and accumulated on the platforms.

Code of Practice for Demolition of Buildings – Scaffoldings

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  • Scaffoldings

Bamboo scaffolds or metal scaffolds shall be used for top down demolition projects. Both bamboo scaffolds and metal scaffolds are considered acceptable provided that they are erected according to the Construction Sites (Safety) Regulations and the codes of practices on scaffolding safety.

Code of Practice for Demolition of Buildings – Lighting

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  • Lighting

A system of temporary lighting shall be provided for the covered walkway and shall be maintained in good order. The average illuminance on the floor level of the covered walkway shall be within the range of 35 lux to 50 lux. The lighting shall be weather-proofed. A recommended lighting layout for typical covered walkway is the installation of luminaries complete with 18 W or 20 W 600 mm long tubular florescent lamps at 3 m spacing.

Code of Practice for Demolition of Buildings – Construction

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  • Construction

As far as practicable, the structural components of the covered walkway and catch platform shall be prefabricated and fastened together on site by bolts so that they can be reused. Site welding shall be minimised in order to reduce the erecting time and potential hazard to pedestrians or vehicular traffic. Prefabricated shoring systems, glass fibre reinforced panels and other ready to use systems shall be used for the hoarding, cover walkway or catch platform installation as much as possible.

Code of Practice for Demolition of Buildings – Proper Use of Covered Walkway

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  • Proper Use of Covered Walkway

Debris shall not be accumulated on the roof of the covered walkway. It shall not be used for any other purposes such as storage of building materials and equipment inside or above the covered walkway.

If it is intended to build a temporary contractor’s shed over the covered walkway, it must be structurally independent of the covered walkway. The roof of the contractor’s shed shall sustain the design load criteria for the catch platform or covered walkway whichever is applicable.

The roof of the covered walkway shall be pitched inwards to better contain the debris and for roof drainage. Upstand edge board of 1.1 m or higher measured from the toe of roof line of the catch platform’s outer edge shall be provided to retain the fallen debris.

Code of Practice for Demolition of Buildings – Design Criteria

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  • Design Criteria

The roof of the covered walkway shall be designed to support a uniformly distributed load of 5 kPa. The catch platform shall be designed to sustain a uniformly distributed load of 5 kPa or a point load of 20 kN acting on an effective area of 300 mm × 300 mm, whichever shall produce the most adverse effect. Design criteria for covered walkway and catch platform are summarised in Table 3.2. The hoarding, covered walkway and catch platform shall be designed to sustain the wind load according to the current Code of Practice on Wind Effects in Hong Kong or its latest equivalent publication. The location of the proposed covered walkway shall be compatible to the existing traffic environment.

Typical details for the catch platform and covered walkway are illustrated in Figure 3.2

Code of Practice for Demolition of Buildings – Hoarding and Covered Walkway Dimensions

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  • Dimensions

A minimum vertical clearance of 2.3 m shall be provided for the covered walkway. A minimum clear width of 1.1m is required for hoarding/covered walkways sited on a carriageway. As regards hoarding/covered walkways on a footpath, the clear width should be related to the existing pavement as set out in Table 3.1. The required clear width must not be obstructed in any manner e.g. by traffic sign, temporary supports, scaffoldings or the like. The width of the catch platform shall not be less than 2 m when it abuts a street and may be reduced by the amount of set back of the building. Separation distance between the walkway cover and the catch platform shall be individually determined according to the design need, e.g. maintenance. A minimum clearance of 5.5 m shall be maintained for the catch platform within a minimum distance of 500mm from edge of a carriageway unless otherwise agreed by the Highways Department. 5.5m clear headroom over gantry shall be maintained as far as practicable.

Table 3.1             Width of Covered Walkway

Existing Pavement WidthMinimum Clear Width in Walkway
2.5 m or lessNormally 1.5m minimum. Exemption may be considered if the pavement is of insufficient width
over 2.5 m to 3 mWidth of the pavement minus 0.8m subject to a maximum of 2 m
Over 3 m2 m

Code of Practice for Demolition of Buildings – Requirements for Hoarding Covered Walkway and Catch Platform

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  • Requirements    for   Hoarding,    Covered   Walkway                              and  Catch Platform

The criteria for use of covered walkway for a site depend on the height of the building being demolished and its proximity to the vehicular and/or pedestrian traffic. The requirements for hoarding, covered walkway and catch platform are described in the following:

  • For buildings that have a clear space between the building line and the lot boundary equal to or more than the building height (hereinafter referred to as clear space), only hoarding shall be required;
    • Covered walkway shall be provided for building with clear space less than the building height;
    • Covered walkway with catch platform shall be provided for buildings with clear space less than half the building height. No catch platform is required for building less than 4 m high;
    • The hoarding and/or covered walkway shall be provided along the full length of the site boundary adjacent to public access.
    • The requirements for hoarding, covered walkway and catch platform are illustrated in Figure 3.1.

Code of Practice for Demolition of Buildings – Hoarding and Covered Walkway

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  1. Hoarding and Covered Walkway

The primary purpose of hoarding and covered walkway is to provide protection of the public during the construction or demolition of buildings. Generally, hoarding isolates the demolition site from the public, thus preventing unauthorized access and trespassing. The covered walkway, in conjunction with catch platform, provides additional protection to the pedestrian traffic against falling debris. The Authorized Person / Registered Structural Engineer shall design them to suit individual site circumstances. Suggested designs for hoarding, covered walkway and catch platform are listed in the following: