DfS consultancy
We act for developers who delegate their DfS duties, coordinating the DfS review process with the design and construction teams for projects in Singapore, and Safety by Design under OSHCIM in Malaysia.
Design for Safety · Singapore and international
Turn the design.
Remove the risk at source.
JOH Safety Consultancy helps developers, designers and contractors find and remove foreseeable risks while a project is still on the drawing board, so fewer people have to rely on a helmet to stay safe.
Our philosophy · The meaning of our logo
The helmet is the last line of defence. The gear is where safety begins.
Every worker on site wears a safety helmet. It is basic and it is essential, but by the time a helmet does its job, something has already gone wrong.
Read more: the meaning of our logo and our DfS philosophyShow less
Personal protective equipment (PPE) sits at the bottom of the hierarchy of controls. It protects only the person wearing it, and only if it is the right equipment and is used correctly. When every other control has failed, PPE is what is left.
About the helmet in our logo: the helmet stands for all PPE, including safety helmets, safety glasses and face shields, earmuffs and earplugs, respirators, gloves, safety shoes, full-body harnesses with double lanyards and shock absorbers, and self-retracting lifelines. We chose the helmet as the most familiar symbol of PPE, the last line of defence in the hierarchy of controls.
Design for Safety works from the top of the hierarchy: eliminating the design risk in the design plan itself. Under the WSH (Design for Safety) Regulations, the developer appoints competent designers, and the designer prepares a design plan for the structure that eliminates all foreseeable design risks, so far as is reasonably practicable. Where a design risk cannot reasonably be eliminated, the designer modifies the design plan to reduce it as low as is reasonably practicable, at its source, using collective protective measures in preference to individual ones such as PPE.
The rotating gear in our logo stands for innovative engineering and design solutions. Turning the wheel means questioning the design plan and innovating until the design risk is removed at source. Remove the design risk from the structure, and the people downstream no longer have to rely on PPE against it.
That is the thinking behind DfS. Decisions made at project inception, concept and detailed design protect the people who will build the structure, use it as a workplace, clean and maintain it, alter it, and one day demolish it. These are the affected persons, and few of them will ever have a say in the design.
Our consultancy work is to help every developer, designer and contractor (DDC) turn that wheel early: review the life-cycle risks met on past projects, and build the lessons into their SOPs and specifications. That way the safety helmet stays what it was meant to be: the last line of defence, not the first.
The safety helmet
Stands for all PPE: worker safety at its most basic, and the last line of defence when other controls fall short.
The turning gear
Innovative engineering and design solutions. Turn the wheel to design out the design risk at source and protect the affected persons.
Hierarchy of controls, most effective first
1EliminationDesign out
2Substitution
3Engineering controls
4Administrative controls
5Personal protective equipmentLast line
Our DfS philosophy
Look inwards first
Design for Safety does not begin with a search for new solutions elsewhere. It begins with the developer, designer and contractor (DDC) looking inwards at their own thinking. Which risks have come up on past projects, at every stage of the life cycle? Could they have been designed out at source?
The answers belong in each organisation's own standard operating procedures (SOPs) and in its general and particular specifications. Once a known risk is designed out in the specification, every new project starts from a safer baseline, and the DfS review can concentrate on what is genuinely new.
Where this has not happened, the DfS review process has produced a great deal of unnecessary paperwork. The same life-cycle risks are raised project after project and recorded again and again, yet never properly reviewed, mitigated and written into the DDC's SOPs and specifications.
DfS has been mandatory in Singapore for ten years. By now, every developer, designer and contractor should have comprehensive SOPs and specifications, both general and particular, that capture what past projects have taught them.
- 1Look backGather the life-cycle risks met on past projects, from construction through to maintenance and demolition.
- 2Design out at sourceAsk whether each risk can be eliminated or reduced in the design itself.
- 3Write it inBuild the solution into DDC SOPs and the general and particular specifications.
- 4Start saferThe next project begins from that baseline, and the DfS review focuses on new risks, not old paperwork.
Vision
To be the leading consultancy for well-being, safety and health in the region.
Mission
- Be a strong voice for safety and health, and champion risk management built on sound professional advice.
- Build safety and health competency through practical, interactive training and workshops.
- Give stakeholders a common platform for open discussion and shared learning.
- Support national and regional safety and health goals, including Vision Zero.
Services
What we do
Advice and hands-on support across the project life cycle, from the first design brief to post-construction review.
DfS coaching and audit
Coaching for senior management and project managers on putting DfS into practice. Audits check documents, inspect the site and interview key personnel to verify implementation and compliance.
Post-construction DfS review
A site walk to identify residual design risks and recommend further controls, bringing those risks down to as low as reasonably practicable before handover.
Customised DfS and WSH training
In-house courses built around your projects and your people, from awareness sessions for management to hands-on DfS review workshops.
WSH site inspection
Regular weekly, fortnightly or monthly inspections, appointed by the developer or contractor.
Incident and accident investigation
Fact-based investigation through document review, site inspection and interviews, focused on root causes to prevent a repeat. Expert witness support where required.
Temporary structural works
Design with calculations, endorsement and certificate of supervision for temporary structural works, and structural assessment of existing structures before A&A works.
Risk management training
Training that helps every stakeholder spot risk at source and choose effective controls, pitched to their experience and role.
ISO management systems
Training and consultancy for ISO 9001, ISO 14001 and ISO 45001, keeping the system practical rather than paper-heavy.
The DfS life-cycle approach
Risk is easiest to remove at the earliest stage
DfS considerations follow a building or structure through its whole life. The earlier a design risk is found, the more options there are to design it out.
- Stage 1
Project inception
Site location, orientation of structures, links to existing facilities and the client's own DfS requirements.
- Stage 2
Concept and detailed design
Site constraints, surroundings, traffic and the structure's architectural and structural design, including access and buildability.
- Stage 3
Pre-construction planning and construction
Temporary works, specialist contractor design, site layout and the residual design risks handed to the builder.
- Stage 4
Operation and maintenance
Safe cleaning, repair, equipment replacement and A&A works across the life of the building.
- Stage 5
Demolition
Decommissioning and demolition, planned for from the start rather than left to the end.
The Workplace Safety and Health (Design for Safety) Regulations 2015 have applied since 1 August 2016 to projects involving construction work of $10 million or more. Developers, designers and contractors are required to work together to identify foreseeable design risks, eliminate or reduce them as far as reasonably practicable, and record them in a DfS register that stays with the building.
Upcoming training courses
Public courses with Jason Oh as trainer
Both courses are run by IES Academy. Registration and payment go through IES Academy; the flyer has the full schedule, fees and terms.
5-Day Course for Appointed Person – Lifting Operations (47th run)
For managers, engineers and WSH officers who plan safe systems of work for lifting operations, select cranes or manage crane use on site. Jason covers the WSH legislation, the Code of Practice on Safe Lifting Operations, DfMA and PPVC, and crane-location risk assessment.
- Dates
- 19, 20, 21, 23 and 25 Nov 2026; written exam 27 Nov 2026
- Venue
- IES Academy @ Jurong East and BCA Academy @ Braddell
- Fees
- $2,834 (IES members); $3,052 (non-members)
- Entry
- Engineering degree, or local engineering diploma with 1 to 3 years of relevant experience, plus working knowledge of rigging, signalling and lifting
- Enquiries
- IES Academy, 6463 9211
Perform Design for Safety Professional Duties (15th run)
Formerly the Design for Safety for Professionals (DfSP) course. For professional engineers, architects, designers, project managers and surveyors preparing to act as DfS Professionals: facilitating the design review process, keeping the DfS records, and passing safety and health information between stakeholders.
- Dates
- Thu 17 and Fri 18 Dec 2026, 9 am to 5.30 pm
- Venue
- IES Academy @ Jurong East, 80 Jurong East Street 21, #04-10
- Fees
- $1,090 with GST; from $390 with GST after SkillsFuture funding, for those eligible
- Entry
- Registered PE or architect with a practising certificate, or 10 years of relevant experience (at least 5 in design) with a recognised degree
- Enquiries
- Christine Lau, IES Academy, 6461 1248, [email protected]
Course dates, fees and trainers are set by IES Academy and may change. Please check with IES Academy before registering.
Training
Design for Safety courses
Course content follows the WSH Guidelines on Design for Safety (2022) and the DfS tools introduced with them.
Introduction to Design for Safety
For anyone new to DfS on a building or construction project.
- WSH (Design for Safety) Regulations 2015
- What “reasonably practicable” means
- Roles of developers, designers, contractors, registered proprietors and subsidiary management corporations
- The DfS register
- Case studies
One-day workshop for developers and designers
How DfS adds value to design decisions and long-term maintenance.
- DfS considerations by life-cycle stage
- Red, Amber, Green (RAG) lists
- Hazard-based DfS checklists
- Design risk, residual design risk and construction risk
- DfS review workshop
One-day workshop for builders and contractors
Managing residual design risks handed over to the construction team.
- Roles of all stakeholders under the DfS Regulations
- Code of Practice on WSH Risk Management
- Contractor risk assessment versus design risk assessment
- Proposing reasonably practicable control measures
- Safety and health information at project completion
Safety by Design for Malaysia
For clients, principal designers and principal contractors under OSHCIM (DOSH).
- Duty holders under OSHCIM
- Design review stages DR-RULE 1, 2 and 3
- HIRARC and risk control
- Pre-construction information, construction phase plan and safety and health file
- Design review workshop
DatesBy arrangement
Time9 am to 5 pm
Class sizeMinimum 5 participants
CustomisationAvailable on request
People
Our team
Engineers and safety professionals who have helped write the standards and train the people who apply them.
Jason Oh
Qualifications and roles
- DfS Professional
- B.Eng (Hons) (Civil), MSc (SHE Tech), FIES
- 30 years of construction, design and management experience
- Chairman, IES Vision Zero
- DfS Lead Trainer, IES Academy, since 2010; Adjunct Lecturer, NUS
- Convenor, SS 617 (lifting persons); Co-Convenor, SS 559 (tower cranes)
- Review committees for SS 497, SS 536, SS 562 and SS 598
Dr Foo Swee Cheng
Qualifications and roles
- Adjunct Associate Professor
- PhD (Chem Eng), MSc (Ind Hyg), MEng (Ind Eng)
- FIES, MSLP, MACGIH, MAICE
- Past Chairman, Health and Safety Engineering Technical Committee, IES
- Former IES Council Member
Dr Sin Siang Meng
Qualifications and roles
- Associate Professor
- PhD (Incident Mgt), MBA (Business Resilience), MSc (SHE Tech), BSc (Chemistry and Biochemistry)
- FIFireE, MIES, MSLP
- Certified Fire and Explosion Investigator (CFEI, USA)
- Certified in Emergency Planning (UK); Business Continuity Certified Practitioner and Lead Auditor
Er Teng Chin Seng
Qualifications and roles
- B.A.Sc (Elect Eng), MBA
- PEng (S), CPEng (Aust), Licensed Electrical Engineer
- Authorised Examiner (AE)
- Co-Convenor, SS 617 (lifting persons) and SS 559 (tower cranes)
- Past President, ACES (2016 to 2017)
Er Ling Shiang Yun
Qualifications and roles
- B.Eng (Mech), MSc (Bldg Sc), MSc (SHE Tech); Sr. MIES, MEESS
- Registered Professional Engineer (Mechanical)
- Certified DfS Professional (2012)
- MOM-approved Noise Control Officer; MOM Workplace Auditor
- Convenor, CP 99 Industrial Noise Control
Track record
Training, talks and standards work
Training delivered
- 2024Perform Design for Safety Professional Duties: WSH Guidelines on DfS (2022), IES Academy
- 20245-day course for Appointed Persons (Lifting Operations), covering the ACOPs, SS 536:2023 and SS 559:2022
- —SISO: Design for Safety, one-day workshop for WSH professionals
- —Chiu Teng Construction: one-day DfS workshop for contractors
- —Excel Precast: one-day DfS workshop for designers
Invited speaker
- 2026City Developments Limited: CDL 5-Star EHS Seminar, New Regulation Updates for Demolition (SS 557:2026)
- 2018UTM Institute for Oil and Gas, Kuala Lumpur: Safe by Design through OSH Construction Industry Management
- 2018City Developments Limited: CDL 5-Star EHS Seminar
- 2018CIDB Malaysia: OSHCIM 2018, Build Perfect
- 2018CIDB and KPH Synergy: Re-engineering Safety by Design, Breaking the Pattern
- 2018DOSH Malaysia: two-day OSHCIM management training
Professional representation
- 2026Panel of Judges (IES representative), LTA Annual Safety, Health and Environment Awards Convention
- 2018Judge, IES Prestigious Engineering Achievement Awards
- 2017IOSH representative, 18-member tripartite WSH delegation to Australia led by the Minister of State
- 2017IES Assessment Committee, Fire Safety Design Excellence Awards
- —Standards committees for tower cranes, mobile cranes and lifting persons (SS 559, SS 536, SS 617)
In the media
News and events
Recent events
20 Oct 2026
Standards Partners Appreciation Lunch 2026
- Time
- 10.00 am networking, followed by lunch
- Venue
- Polaris Grand Ballroom, Level 1, Novotel Singapore on Stevens
- Hosts
- Manufacturing Standards Committee (MSC) and Safety & Quality Standards Committee (SQSC), Singapore Standards Council
Jason Oh joined fellow standards partners at the appreciation lunch, which recognised the volunteers who help develop Singapore Standards. It was a good chance to catch up with fellow working-group members and committee colleagues who give their time to keep safety standards current for industry.
23 Sep 2026
CDL 5-Star EHS Seminar 2026
- Time
- 3.00 pm; Jason's talk at 4.00 pm
- Venue
- Union Square Residences Sales Gallery
- Host
- City Developments Limited (CDL)
- Role
- Speaker
Jason spoke on New Regulation Updates for Demolition, covering the revised SS 557:2026 Code of Practice for Demolition. BCA announced its adoption on 2 June 2026. It replaces SS 557:2010 and reflects current demolition technologies and stronger structural safety requirements. The key changes covered:
- Structural appraisal and stability: for buildings more than 40 years old, or where the strength or quality of the concrete is in doubt, suitable tests must be carried out to verify structural integrity.
- Wider scope before demolition: specific guidance for PPVC (prefabricated prefinished volumetric construction), mass engineered timber (MET) and marine-based structures, and for high-reach machines, including their operation and safety buffer zones.
- Safe working zones: new precautions for prestressed and post-tensioned members, including the hazards of de-tensioning tendons.
- Safety and environment: exclusion zones and safety working spaces, closer alignment with SS 602:2025 on noise control, and real-time dust and vibration monitoring in high-density areas.
For new project applications submitted to URA for planning permission on or after 1 December 2026, BCA expects demolition plans to comply with SS 557:2026.
22 Sep 2026
LTA Annual Safety, Health and Environment Awards Convention 2026
- Venue
- Max Atria, Singapore Expo
- Host
- Land Transport Authority (LTA)
- Role
- Awards assessor, Panel of Judges (IES representative)
Congratulations to all the winners at the 28th ASAC: 90 awards went to 63 organisations for their commitment to safety, health and environmental excellence. The top award, the LTA Contractors Champion Shield, went to Hwa Seng Builder Pte Ltd for its work on the Jurong Region Line.
As an awards assessor representing IES, Jason saw how construction risks were eliminated by changing the design plan, reducing design risks so far as reasonably practicable while taking actual site challenges into account. LTA regularly reviews its SOPs and technical specifications with Design for Safety in mind, feeding lessons from past projects back into them. It is a good example of how a developer of large and complex infrastructure can achieve SHE excellence.
Contact
Discuss your project or course
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NameJason Oh, Principal Consultant
Phone+65 9021 2992
Email[email protected]
Office111 North Bridge Road, #21-01 Peninsula Plaza, Singapore 179098
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