What Is a Residual Design Risk?
A residual design risk is a foreseeable risk that remains after design measures have been applied to eliminate or reduce it as far as reasonably practicable. It is not a failure of the process — it is the information the process is meant to surface and communicate.
Direct answer
Not every risk can be designed out. Where elimination is not reasonably practicable, the DfS process expects the risk to be reduced at source, as far as reasonably practicable, with collective protective measures generally preferred over individual protective measures. What is left after that process is the residual design risk — and it should be documented, not left implicit.
The risk-reduction hierarchy
Eliminate
Remove the hazard through design wherever reasonably practicable.
Reduce at source
Where elimination isn't practicable, reduce the risk at its source through design.
Collective protection
Prefer measures that protect everyone exposed, over relying on individual protective equipment.
Document & communicate
What remains is the residual risk — recorded in the DfS Register and communicated to those affected.
Why communication matters
A residual risk that is identified but not communicated to the people who will face it — a maintenance contractor, a future façade cleaner, a demolition crew years later — defeats much of the purpose of recording it. This is why the DfS Register is issued to the Developer, Designers and Contractor, and why it should be handed over at project completion in a state that remains useful to whoever operates or later alters the building.
See how residual risks are recorded in the DfS Register →.
Official references
- GuidanceWSH Council, Workplace Safety and Health Guidelines — Design for Safety — official source →
- RegulationWorkplace Safety and Health (Design for Safety) Regulations 2015 — Singapore Statutes Online — official source →