Frequently asked questions

Adoption of Smart Site Safety System to provide qualified supervision of building works involving the use of mobile plants and tower cranes

  1. With effect from 1 July 2024, BD will impose conditions* under item 6 of section 17(1) of the Buildings Ordinance (BO) upon granting the first approval of superstructure plans or major revision of superstructure plans requiring the registered contractor (RC) to provide qualified supervision of building works involving the use of mobile plants and tower cranes by adopting automated alert systems, namely the Mobile Plant Alert System and Tower Crane Alert System if the estimated cost of building works exceeds $30 million.

    Upon application for consent for commencement and carrying out of superstructure works, a declaration by the Authorized Person on whether the estimated cost of building works of the project exceeds $30 million is required to be submitted under regulation 10 of the Building (Administration) Regulations. For a project with an estimated cost exceeding $30 million, the said relevant conditions* will be imposed upon granting the consent requiring the RC to provide qualified site supervision of the building works involving the use of mobile plants and tower cranes by adopting the Mobile Plant Alert System and Tower Crane Alert System.

    *The relevant conditions should be referred to item 1g of Table A.

  2. The Mobile Plant Alert System should alert the mobile plant operator and any site personnel encroaching the mobile plant danger zone perimeter of the risk of being run over or hit by the plant moving components. The automated warning system should include adequate number of sensors installed on the mobile plant chassis and movable superstructures to ensure 360° coverage around the mobile plant danger zone perimeter. The danger zone of the mobile plant operation should be determined by the Safety Officer1 according to risk assessment but in general, the extent of the danger zone should be not less than 2m from any part of the mobile plant.

    1Safety Officer employed pursuant to the Factories and Industrial Undertakings (Safety Officers and Safety Supervisors) Regulations.

  3. The Tower Crane Alert System should alert tower crane operator and any site personnel encroaching upon the tower crane loading/unloading danger zone perimeter of the risk of being hit by the moving load under the crane hook. The automated warning system should include adequate number of sensors installed on or around the tower crane to ensure full coverage around the loading/unloading area danger zone perimeter at all floor levels involved. The loading/unloading danger zone of the tower crane operation should be determined by the Safety Officer1, according to risk assessment but in general, the extent of the danger zone should be not less than a radius of 7m from the crane hook. The minimum clearance between the load being lifted and the loading/unloading area activating the automatic warning system should be determined by the Safety Officer according to risk assessment but in general, should be not less than 3m.

    1Safety Officer employed pursuant to the Factories and Industrial Undertakings (Safety Officers and Safety Supervisors) Regulations.

  4. Under the BO, the RC should ensure that the mobile plants and tower cranes used for the building works are equipped with the Mobile Plant Alert System and Tower Crane Alert System under the Smart Site Safety System. In this connection, the responsibilities and duties of authorized signatory (AS) of the RC, the AS’s representative and the technically competent persons (TCP) for site supervision under the RC stream are as follows:

    1. An implementation plan should be prepared by the AS or under the supervision of the AS for the adoption of the alert systems. The plan should include, but not limited to, the types of mobile plants and/or tower cranes to be used, the automated alert systems to be used, the definition of danger zones, a brief description of their operation, and the fallback measures for special circumstances (e.g. system failure);
    2. The AS and the AS's Representative should ensure that the said implementation plan is properly executed on site; and
    3. The TCP T11 and TCP T32 should check that the alert systems are properly installed and operating to alert the plant operators and any site personnel encroaching the danger zones. They should report according to the implementation plan for any necessary repairs/rectification whenever a malfunction is identified.

    1T1 should hold a certificate or diploma and have minimum total relevant working experience of 2 years, of which at least one year must be local experience. T1 should check the alert system once a day.

    2T3 should hold a higher certificate or higher diploma with minimum total relevant working experience of 5 years, or hold a degree with minimum total relevant working experience of 2 years, of which at least one year must be local experience. T3 should check the alert system once a week.

  5. "Mobile plant" generally includes all heavy-type mobile plants, such as bulldozer, compactor, crawler crane, dumper, excavator, gantry crane, grader, loader, scraper, truck-mounted crane and wheeled telescopic mobile crane. Vehicles or mechanical equipment commonly used for conveying materials and/or personnel such as fork-lift truck, lorry, power-operated elevating work platform and truck, or plants which are stationed on site for less than one day such as concrete mixer, shotcrete truck and water pump truck are excluded. The list of mobile plants may be reviewed from time to time when more experience is gained taking into account the development of the related technology.

  6. We understand that there may be system failure to the two automated alert systems. As such, while we emphasise the need for the RC to ensure the normal operation of the system, we also require the RC to clearly provide in their implementation plan the fallback measures for special circumstances (e.g. system failure). The RC must also complete the rectification within a reasonable time.

  7. The RC should take into account factors such as relevant statutory requirements (if any), the actual site situation and the risk assessment prepared by the Safety Officer1, to determine the extent of the danger zones, the type of the automated alert systems or other special measures to deal with hazards caused by narrow site environments.

    1Safety Officer employed pursuant to the Factories and Industrial Undertakings (Safety Officers and Safety Supervisors) Regulations.

  8. The Mobile Plant Alert System is aimed to immediately alert both the plant operators and any site personnel encroaching the danger zone, where there is a potential risk of being run over or hit by the plant moving superstructure and/or the moving load. In view of the actual conditions on the site, if any part of the movable component of the mobile plant is higher than 2 metres from the ground when it is operating at a fixed position, the risk of being run over or hit by the movable superstructures of the plant does not exist. Under this condition, the mobile plant does not need to be equipped with sensors. Nonetheless, RC are still required to provide adequate and effective crowd management measures to separate danger zone to prevent site personnel from accidentally entering the zone. RC are required to clearly include the relevant arrangements in their implementation plans.

  9. The operation of truck-mounted cranes on construction sites involves building works and therefore needs to be included in the definition of "mobile plant" in this mandatory requirement. In view of the actual operation of truck-mounted cranes on construction sites and the application of Mobile Plant Alert Systems, if the truck-mounted cranes stay on the site for less than one day, they are not included in the definition of mobile plant. Otherwise, the truck-mounted cranes must be equipped with Mobile Plant Alert System to comply with the conditions imposed under the BO.

  10. Generally speaking, BD will first issue an advisory letter, requiring the authorized person to find out the reasons from the RC for failing to comply with the imposed conditions, and remind the RC to comply with the imposed conditions.

    If the RC fails to comply with the imposed conditions without reasonable excuse, BD will instigate an investigation in accordance with the BO. If the RC is found to have committed an offence under the BO during the investigation, serious follow-up action will be considered, including prosecution against the contractor concerned and/or referring the case to the relevant disciplinary committee for disciplinary hearing. If necessary, the case will also be referred to other authorities for follow-up investigation and appropriate action.

    According to section 40(2AB) of the BO, it is an offence for a contractor or person contravening the conditions imposed under item 6 of column A of Table 17(1) of the BO. The maximum penalty on conviction is a fine of $150,000 and imprisonment for 1 year.

  11. BD will take a series of measures, including checking the implementation plan for adopting the Mobile Plant Alert System and Tower Crane Alert System prepared by the RC during site audit inspections, checking the site monitoring records of the TCP, and checking whether the relevant alert systems are properly installed as appropriate, and in normal operation. BD will also monitor whether the RC has adopted the Smart Site Safety System in compliance with the imposed conditions.

    BD will also investigate and follow up if it receives reports or referrals about RCs who have not adopted the alert systems.

    *Please refer to BD web site for "Site Monitoring".

  12. Owing to the difference in the regulatory system of capital works and private works, the technical requirements stipulated under the Technical Circular (Works) No. 3/2023 on Smart Site Safety System are for reference only. For example, the provision of centralized management platform and recording function of the automated alert system is not required under the mandatory requirements.

    When preparing the implementation plan for the Mobile Plant Alert System and Tower Crane Alert System, RC should select automated alert system (including installation of the system at appropriate positions and provision of adequate number of sensors) based on the circumstances of a project for compliance with the performance requirements of the systems stated in question 2 and question 3 above. Also, products of the automated alert systems under the Smart Site Safety System on the Construction Innovation and Technology Fund Pre-approved List are generally acceptable.

    Having said that, BD strongly recommends that the functional performance of the alert systems to be adopted for use in carrying out building works should comply with the technical requirements stipulated under the Technical Circular as far as practicable.

    *Please refer to Construction Industry Council website for products of the automated alert systems under the "Smart Site Safety System" on the Construction Innovation and Technology Fund Pre-approved List

    *Please refer to Development Bureau website for Development Bureau Technical Circular (Works) No. 3/2023

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