Hong Kong 4S (Smart Site Safety System) Requirements Guide — 2026

What is 4S?

Under DEVB Technical Circular (Works) No. 3/2023, 4S has three parts: smart safety devices, a communication network, and a Centralised Management Platform (CMP) that brings device data together and raises alerts. The CMP may be integrated with the Digital Works Supervision System (DWSS).

The official Chinese name is 「安全智慧工地」系統; in English it is the Smart Site Safety System, abbreviated 4S or SSSS.

Sources：[1][2]

4S elements at a glance

The table lists the 4S elements in the DEVB circular and marks what BD requires on private works. The right-hand column shows related New Forward solutions; specifications must be checked item by item against each contract or approval condition.

Sources：[1][4]

Public works: DEVB TC(W) No. 3/2023 (updated July 2026)

• Capital works contracts with an estimated sum over HK$30M tendered on or after 27 Feb 2023 must adopt 4S; earlier-tendered contracts of that size must also adopt it, and existing contracts are strongly recommended to add it by variation order.
• The 4S cost should normally not exceed HK$10M or 1% of the contract sum, whichever is lower. Contractor performance feeds into the safety performance score card.
• Update of 10 Jul 2026: other public works contracts over HK$30M (such as maintenance and term contracts) shall also adopt 4S, and three device types were added — smart monitoring for MEWPs, smart monitoring for scaffolding putlogs, and smart fire and smoke detection.
• The annexes are sample contract clauses, not a fixed checklist; project teams select suitable devices according to site risks.
• The sample specification asks the CMP to control all components on one platform with highlighted pop-up alerts, support at least 30 concurrent users, keep data for at least 3 months, run in a browser over HTTPS without extra software, and use at least 256-bit encryption.

Sources：[1]

Private works: Buildings Department extension from 1 July 2025

• Applies where the estimated total cost of building works exceeds HK$30M (counted for the whole development project) and mobile plant and/or tower cranes are used.
• Covers demolition, site formation, excavation and lateral support (ELS), foundation, pile cap and superstructure works, plus alteration and addition works involving structural works. The earlier arrangement from July 2024 covered superstructure only.
• BD imposes it as approval/consent conditions under the Buildings Ordinance, requiring two systems: a Mobile Plant Alert System and a Tower Crane Alert System. BD does not require a CMP or other 4S elements on private sites.
• "Mobile plant" generally means heavy plant such as bulldozers, compactors, crawler cranes, dumpers, excavators, gantry cranes, graders, loaders, scrapers, truck-mounted cranes and wheeled telescopic mobile cranes; fork-lift trucks, lorries, power-operated elevating work platforms and plant on site for less than a day (e.g. concrete mixers) are excluded.
• Danger zones follow a risk assessment; in general at least 2 m from any part of a mobile plant and at least a 7 m radius for tower-crane lifting, with full 360° coverage around mobile plant.
• Breaching the conditions is an offence under section 40(2AB) of the Buildings Ordinance, with a maximum fine of HK$150,000 and one year's imprisonment.
• BD does not approve individual products; products on the CITF Pre-approved List are generally acceptable.

Sources：[2][3][4][5]

4S Labelling Scheme

• Launched by CIC with DEVB in May 2024. The label is awarded to projects, not products; only the main contractor can apply, and the 4S devices do not need to be on the CITF Pre-approved List.
• Assessment covers risk identification by the safety officer under the Labour Department's Code of Practice on Safety Management, consistent use of 4S against those risks, device location plans and wearable arrangements, a site inspection of installation and continuous operation, and regular function checks with a backup plan.
• CIC inspects about a month after application and the process takes about three months; approved projects receive an e-label and a plaque with a unique ID for the site entrance. The label is valid for one year from approval and can be renewed.
• CIC currently states that application and renewal fees are waived for applications submitted on or before 31 December 2026.
• CIC carries out surprise inspections of labelled sites and confiscates the label if 4S is not properly adopted; the Labour Department also refers such cases to CIC via DEVB.

Sources：[6][7][8][11]

CITF funding (private works)

• Since 1 Apr 2023, CITF funds 4S only on private works sites, as 4S is already mandatory on public works.
• Procurement of 4S products is generally funded on a 70% matching basis (80% for locally developed products); rental is generally 50%. From 1 May 2026, SMEs with fewer than 50 employees receive an extra 10%.
• Each applicant has an additional HK$1.5M ceiling reserved for 4S, after which the general allowance can be used; 4S products count as safety products with a cap of HK$2M per technology for procurement.
• Ancillary costs such as extra network (gateways, 4G/5G SIMs), additional 4S staff (up to HK$20,000 per site per month) and maintenance support can be funded under the guide.
• Apply before making any financial commitment (signing or paying); grants are based on the lowest quotation and the approved product price, subject to approval.
• CITF keeps a 4S Pre-approved List in ten categories: CMP, digitised tracking, permit-to-work, e-lock, mobile plant alert, tower crane alert, wearables, AI, confined space and VR safety training.

Sources：[9][10]

Latest developments in 2026

• In a LegCo reply on 24 Jun 2026, the Secretary for Development said about 60% of new construction and maintenance projects over HK$30M have adopted 4S, and the industry's overall accident rate fell by about 20% from 2023 to 2025.
• The same reply said DEVB now requires resident site staff and contractors' frontline staff on all public works contracts to wear body-worn video cameras (BWVCs) during site inspections — not part of 4S, but part of the same push for site technology.
• At Construction Safety Week in August 2026 the Government said about 80% of Hong Kong construction sites have installed 4S devices, and it aims to make 4S a standard feature.

Sources：[11][12]

FAQ

Official sources

1. [1] DEVB Technical Circular (Works) No. 3/2023 – Smart Site Safety System (incl. 10 Jul 2026 update)
2. [2] Buildings Department Circular Letter (31 Mar 2025): Extension of Adopting Smart Site Safety System
3. [3] Buildings Department Practice Note APP-162 (rev. Mar 2025)
4. [4] Buildings Department Common Conditions SE-SA31 (07/2025)
5. [5] Buildings Department: FAQ on Smart Site Safety System
6. [6] CIC: Application Guide for 4S Labelling Scheme (Mar 2025)
7. [7] CIC: 4S Labelling Scheme FAQ
8. [8] SDEV press release (20 May 2024): launch of 4S Labelling Scheme
9. [9] Construction Innovation and Technology Fund (CITF) Guide to Application (Aug 2026)
10. [10] CITF: funding for 4S
11. [11] LegCo Question 13 reply (24 Jun 2026, Secretary for Development)
12. [12] Government press release (24 Aug 2026): Construction Safety Week

This page summarises public official documents for reference only and is not legal advice; obligations follow your contract, BD approval conditions and the latest official notices.