Precautionary Measures for Public and Building Safety during Rainy and Typhoon Seasons

Building Owners / Incorporated Owners /
Property Management Companies
Building Professionals /
Registered Contractors

Building Owners / Incorporated Owners / Property Management Companies

From past experience, many public and building safety incidents caused by typhoons or adverse weather conditions could have been avoided if proper precautionary measures have been taken.

Tips on Precautionary Measures

Inspect roof, podium, flat roof and basement (including car park) to ensure surface water drains and rainwater manholes are in good working order without blockage;
Inspect all projections and installations at the building exteriors (e.g. scaffolding, signboard, advertisement, decoration, photovoltaic panel and its supporting structure or supporting structure for other building services installation) as well as pay attention and make necessary arrangement to ensure such are in secure and safe conditions;
Provide suitable pumping equipment at areas of flooding risk such as electrical and mechanical plant rooms and basement car park;
Inspect slopes and retaining walls within the development to ascertain any anomalies (e.g. cracks, drains blocked, mud oozing, fallen rocks);
Provide proper protection materials or devices for windows, glass doors and glass panels in exposed positions, and to ensure all openable windows (including curtain walls) are securely closed and locked;
Ensure gondola (if any) parked at safe location and is properly secured; and
Remove/relocate the potential target/object that may be hit by a fallen tree/branch, or restrict access/cordon off the area within the possible tree fall zone.

Remember...

Please impress upon your property management company staff to ensure that the suitable precautionary measures are taken.
After inclement weather, please appoint competent persons to carry out inspections and the necessary repair works as soon as possible.

Related Information

Building Professionals / Registered Contractors

Buildings Department may regularly issue circular letters reminding building professionals and registered contractors the prevention measures at construction sites on the safety of scaffolding and tower cranes as well as flood prevention during rainy and typhoon seasons. Please refer to "Related Information" for details.

Safety of Scaffolding

From past experience, most of the incidents involving the collapse of or related to scaffolding could have been avoided if the following site measures had been taken:

sufficient ties of adequate strength are provided to secure the cantilever portion at the topmost floor;
the height above the topmost floor should not be over-extended (maximum one floor);
adequate putlogs, ties, struts, bracing and steel brackets are provided to secure the scaffolding framework;
plastic sheeting should be removed and the scaffolding above the topmost floor should be lowered to not more than half of the floor height under safe circumstances when a tropical cyclone warning signal or a strong monsoon signal is announced; and
no loose materials should be placed on/near any scaffolding, or near the periphery of the site.

Remember...

Please impress upon on the importance of the safety of scaffolding and ensure that the above site measures are taken in all scaffolding. When the building works have been completed, the related scaffolding should be dismantled as soon as possible. Also, any scaffolding which remains idle should be promptly removed.

Safety of Tower Crane

With regard to the safety of tower cranes in construction sites during typhoon, suitable safety precautionary measures should be drawn up with regard to the types of crane towers being used, surrounding site conditions and the tower crane manufacturers’ recommendations. In general, the following safety precautionary measures against strong wind may be taken:

The main jib should be slewed to the side of the tower away from the wind, and then put into free slew. However, care must be taken to ensure that the jib would not collide with adjacent structures or overhead power cables;
The trolley of the crane with horizontal trolley jib should be placed near to the tower at minimum radius and the hook should be raised to its highest position;
The jib of luffing jib crane (including the articulated jib crane) should be brought to a position at 15° to the horizontal or other position according to the manufacturer’s recommendation and the hook should be raised to its highest position;
If the manufacturer recommends to tie the jib and/or the hook to the specified anchorage points above the slewing ring, it should be made sure that the tie wires are of adequate strength and are tightened up properly; and
If situation warrants, the height of the crane tower above the topmost floor should be lowered as far as practicable.

Remember...

With consideration of construction conditions, works progress and special constraints, tailor-made precautionary measures should be drawn up for different construction sites and the necessary arrangement should be made as early as possible (in particular when extra costs are involved for implementing those measures). Before the approaching of the typhoons, you should make sure that the precautionary measures in place are properly implemented and timely completed.

Updated Contact Information for Emergency Situations

If there are emergency incidents happened on site during the course of typhoon, staff of Buildings Department (BD) may need to contact the authorized person, registered structural engineer and/or registered geotechnical engineer for timely handling those situations. Hence, these registered building professionals are requested to inform BD as soon as possible if there are any changes of their emergency contact telephone number or fax number, by using the letter attached to Practice Note for Authorized Persons, Registered Structural Engineers and Registered Geotechnical Engineers ADM-3.

Follow up Action after Lowering of Typhoon Signals

After lowering of the typhoon signals, the registered contractors should inspect all areas of their construction sites as early as possible, and carry out necessary remedial works immediately if damages are found. Before the resumption of the construction works, it should make sure that the sites are in a safe condition.

Flood Prevention Measures

Improper activities at construction sites causing the occurrence of the following commonly observed impacts on stormwater drainage systems, should be prevented:

Some construction works may have interfaces with stormwater drainage systems including enlargement of, diversion of, or connection to existing stormwater drains. These interfaces will inevitably involve temporary works within the drainage systems. If temporary works are not designed properly to accommodate the flow or not constructed in accordance with the agreed plans, such inadequacy will directly reduce the capacity of the drainage systems and the chance of flooding will then be increased;
Roadside gullies, channels, catchpits and other underground drainage inlets are blocked by unprotected stockpiled excavated materials, misplaced construction and building debris being washed from construction sites, as well as the silt and mud being washed down from the temporary cut/fill slope with inadequate surface protection during heavy rainstorms, resulting in flooding on the roads and causing severe traffic disruption;
Some silt traps provided inside construction sites are not properly designed/provided, or more importantly, not regularly maintained resulting in large amounts of silt and mud, and in some cases cement slurry, entering the stormwater drainage systems and causing serious blockage and damage to the systems. These blockage and damage will substantially increase the risk of flooding in the area;
Temporary site drains may not have been properly designed or connected to intercept and discharge all runoff from construction sites and, as a result, surface runoff overflows from construction sites and causes flooding to areas near the sites. If surface runoff carried with excessive amounts of silt and mud enters and blocks the stormwater drain inlets, flooding will be further aggravated;
Temporary traffic arrangements of some construction sites obstructed the normal functioning of the nearby road drainage systems; and
Discharge of surface water from construction sites through illicit connection into foul sewers. The discharge would contribute to exceptionally high flood flows and deposit of grit and silt at sewage treatment works, causing treatment and pollution problems.

Remember...

Please ensure proper design, maintenance and functioning of temporary drainage for construction sites under your supervision and take all necessary precautionary measures to prevent discharge of construction debris, silt and sediments or cementitious materials into the public drains or sewers to minimise/mitigate the risk of flooding during rainy and typhoon seasons as a result of construction activities. Attention is drawn to the provisions of the Water Pollution Control Ordinance. For any improper/illegal discharges arising from construction activities, the incidents should be reported to the Drainage Services Department or Environmental Protection Department for follow up.