The Roles of QP(D): Understanding Design Qualified Person Responsibilities Under Singapore’s Building Control Act

Introduction

QP(D) stands for Qualified Person for Design in Singapore’s construction industry-a statutory role carrying direct legal responsibility for the preparation, accuracy, and regulatory compliance of building control plans. Under the Building Control Act (Cap. 29), every building project requiring plan submission must have a qualified person appointed for design, making this role foundational to how the built environment is regulated and delivered in Singapore.

This article provides a thorough understanding of QP(D) statutory duties, liability frameworks, coordination requirements with regulatory bodies, and specialization areas such as deep excavation and earth retaining structure design. It is written for developers, contractors, architects, professional engineers, and project team members working on Singapore construction projects that require authority submissions and building control approvals.

In direct terms: QP(D) serves as the statutory design professional who prepares, submits, and takes legal accountability for ensuring building plans comply with BCA regulations, the Urban Redevelopment Authority’s development control guidelines, SCDF fire safety requirements, and all other applicable regulations. A QP(D) is legally accountable for project design integrity and statutory compliance. Under law, the QP(D) bears direct responsibility for design safety and integrity.

By the end of this article, you will understand:

• How QP(D) is defined and appointed under the Building Control Act

• The full scope of QP(D) design responsibilities and legal obligations

• How liability is demarcated between QP(D) and other project stakeholders

• Coordination protocols for deep excavation works, ERSS design, and multi-agency submissions

• Practical solutions for common QP(D) challenges in design and submission phases

Understanding QP(D) Under Singapore’s Building Control Framework

Singapore’s building control system rests on a two-pillar qualified person structure. The role of QP(D) is distinct from that of QP(S), which oversees construction compliance. Together, these two appointments ensure that building works are properly designed before construction begins and properly supervised once works are underway. Understanding where one role ends and the other begins is essential for every participant in the construction industry.

Legal Definition and Statutory Authority

Section 8(1)(a) of the Building Control Act requires the developer to appoint “an appropriate qualified person to prepare the plans of the building works” if no such person has been appointed by the builder. This statutory provision is the legal basis for the QP(D) role-tying the appointment directly to plan preparation responsibilities.

A Qualified Person (QP) must be registered with BOA or PEB. For engineers, registration with the Professional Engineers Board (PEB) is required. For architects, registration with the Board of Architects (BOA) is the pathway. In both cases, the individual must hold a valid practising certificate issued by the relevant board. This valid practising certificate must be current at all times during the QP(D)’s engagement on a project, with annual renewal requirements enforced by the respective regulatory bodies.

The QP is legally responsible for plan submissions in Singapore. Only the QP(D) is allowed to submit formal building plans to regulatory authorities, making this role the gateway through which all proposed works enter the approval system.

QP(D) vs QP(S): Role Demarcation

The distinction between QP(D) and QP(S) is central to Singapore’s building control framework:

• QP(D) is appointed for plan preparation-design, drawings, calculations, regulatory compliance verification, and authority submissions before commencement of building works. The QP(D) is responsible for design integrity, coordination between disciplines (architecture, structural, geotechnical, fire, M&E), and integration of specialist design inputs.

• QP(S) is appointed to supervise the carrying out of works in accordance with approved plans, regulations, and conditions. The QP must supervise construction to ensure compliance with approved plans, report defects or deviations, and enforce site supervision protocols.

Legal accountability boundaries between QP(D) and QP(S) are defined under Building Control Act Section 9. While distinct, their responsibilities intersect: QP(D) must ensure that the design includes appropriate supervision requirements, and must respond when QP(S) flags issues requiring redesign. QP(D) serves as a liaison for design discrepancies during construction. When the same person serves both roles, legal accountability spans both design errors and supervision oversights-a risk that demands careful contractual scope definition.

Professional Qualifications and Competency Requirements

To serve as QP(D), individuals need an accredited degree in architecture or engineering (structural, civil, geotechnical, or related disciplines depending on specialization), plus structured professional experience meeting PEB or BOA requirements. For geotechnical building works involving earth retaining and stabilising structures (ERSS), specialized competence is essential-QP(Geo) designation often arises for the deepest, highest-risk schemes.

Continuing professional development is mandatory for maintaining QP(D) status. Both PEB and BOA require ongoing training courses and adherence to professional ethics. This ensures that qualified persons maintain an in depth understanding of evolving codes, standards, and regulatory expectations throughout their careers.

These qualifications directly translate into specific design obligations, which form the core of QP(D)’s daily professional responsibilities.

Core QP(D) Responsibilities and Design Duties

The QP’s function extends far beyond producing drawings. From plan preparation through authority submission, design review, and compliance verification, QP(D) carries an integrated set of responsibilities that demand both technical excellence and regulatory mastery.

Plan Preparation and Authority Submissions

The QP(D) is responsible for preparing and certifying architectural and structural plans for submission to the BCA. Qualified Persons must submit plans to the BCA through the CORENET X submission system, which serves as Singapore’s digital gateway for building plan submission and approval.

Multi-agency coordination is a defining feature of the QP submission process. Plans must secure approvals or clearances from multiple agencies:

• Urban Redevelopment Authority (URA) for planning permission and development control compliance-written permission from URA must be obtained before BCA submission

• BCA for building control and structural plan approval

• SCDF for fire safety requirements

• PUB for drainage and sewerage

• NEA for environmental control

• NParks for landscaping requirements

• LTA for traffic and transport considerations

Submissions must comply with planning and development control guidelines. The Building Control Act governs authority submissions in Singapore, and all technical drawings must meet prescribed standards for metric notation, scales, annotation, materials specifications, cross-sections, and M&E documentation. A QP’s declaration is crucial for obtaining planning approvals.

Design Review and Compliance Verification

Under Building Control Act Section 9(4), QP(D) must “take all reasonable steps and exercise due diligence to ensure that the building works are designed in accordance with the Act and with the building regulations.” This due diligence requirement is not a checkbox exercise-it demands a thorough understanding of codes, performance requirements, and technical standards across multiple disciplines.

QP(D) must ensure compliance with the Building Control Act and other safety regulations through two pathways:

1. Acceptable solutions prescribed in the BCA Approved Document-these are pre-approved design approaches that satisfy regulatory requirements

2. Alternative solutions that diverge from acceptable solutions but achieve equivalent performance-these require certification by the QP(D) or a specialist approved by the Commissioner of Building Control

They coordinate with specialized engineering teams to ensure design consistency. Integration of specialist designs from geotechnical, fire safety, and M&E consultants falls squarely within QP(D) responsibilities. The QP(D) must verify that specialist inputs are coherent, compatible, and collectively satisfy all submission requirements.

QP(D) evaluates spatial feasibility and conducts risk assessments on adjacent properties. Impact assessments evaluate environmental effects of construction projects and help prevent significant deviations during construction. Qualified Persons must ensure plans meet regulatory requirements across all disciplines before submission.

Independent Parallel Analysis and Design Verification

For structural and geotechnical works, independent checking of design calculations is not optional-it is a regulatory requirement. The accredited checker (AC) system requires independent verification of structural design assumptions, calculations, and drawings. For ERSS or deep excavation classified as geotechnical building works, an AC(Geo) must also be engaged.

QP(D)’s coordination responsibilities with accredited checkers include:

• Providing complete design documentation for independent review

• Responding to queries and resolving discrepancies identified during checking

• Ensuring that AC comments are properly addressed before plan approval

• Maintaining quality assurance protocols throughout the design verification process

The QP(D) remains legally responsible even when an accredited checker is appointed. The AC system provides an additional layer of quality assurance but does not transfer design liability away from the QP(D).

Key points on design verification:

• Independent checking validates design assumptions and catches errors early

• AC involvement is mandatory above certain ERSS depth thresholds and for geotechnical building works

• Design verification documentation forms part of the submission requirements

• QP(D) liability persists regardless of AC appointment

These design verification requirements directly feed into the liability framework that governs QP(D) accountability.

QP(D) Liability Framework and Legal Accountability

The legal obligations attached to QP(D) are among the most consequential in Singapore’s construction industry. Understanding where liability falls-and where it does not-is essential for risk management and decision making by all project stakeholders.

Statutory Duties and Legal Obligations

Section 9 of the Building Control Act establishes the legal obligations that apply during the design phase and beyond:

1. Personal responsibility for plan accuracy: QP(D) must take all reasonable steps and exercise due diligence to ensure design compliance. Non compliance with this duty is a statutory offence.

2. Notification obligations: A QP must report any deviations from approved plans immediately. QPs must notify authorities of any non compliance with plans. The QP must notify the URA of any deviations from approved plans. This extends to informing the Commissioner of Building Control of any contraventions of the act or building regulations that the QP knows or reasonably should know about.

3. Criminal liability: Contravening Section 9 duties can result in fines up to SGD 200,000 and/or imprisonment up to 2 years, with continuing daily fines for ongoing breaches. Failure to conduct periodic structural inspections can lead to fines. Structural inspections are mandated by the Building Control Act.

4. Civil liability: In SYT Consultants Pte Ltd v QBE Insurance (2022), the QP engaged for ERSS design and supervision was found liable when neighbouring properties sustained damage due to excavation works. The developer and builder settled sums of SGD 820,000 and SGD 1,450,000, illustrating how design failures cascade into substantial financial exposure.

5. Professional negligence: In Wei Siang Design Construction v Euro Asset (2018), the architect serving as QP(D) was held responsible for drawings that failed to satisfy URA/BCA conditions-demonstrating that the QP role carries implied assumption of responsibility even for coordination with other professionals.

6. Cessation notification: QP(D) must notify the Commissioner and builder within 14 days if becoming unwilling or unable to continue duties. Failure to do so is itself an offence.

Supply of approved plans is also mandatory-once plans receive plan approval, QP(D) must provide copies to the site supervisor, builder, and QP(S) under Section 9(1)(c), ensuring all parties work from correct documents.

Liability Demarcation Matrix

Responsibility Area	QP(D)	QP(S)	Developer	Builder	Accredited Checker
Plan preparation and design compliance	Primary	None	Appoints QP(D)	May appoint QP(D)	Independent review
Authority submissions	Primary	None	Provides project info	Coordinates logistics	Certifies check
Design integrity and code compliance	Primary	Flags issues	Contractual oversight	None	Validates calculations
Supervision of building works	None (but specifies requirements)	Primary	Appoints QP(S)	Carries out works	None
Notification of deviations	Shared (design-related)	Shared (site-related)	Must be informed	Must be informed	Reports to Commissioner
Record plans and C-Forms	Primary (Form C3)	None	Receives records	Receives records	None
Monitoring design (ERSS)	Primary	Implements monitoring	Contractual oversight	Installs equipment	Reviews design

Professional indemnity insurance is required for engineers serving as QP(D). Insurance coverage must reflect the full scope of engagement, including ERSS design, deep excavation, alternative solutions, and monitoring obligations. The SYT Consultants case demonstrates how insurance coverage disputes can arise when the scope of QP(D) duties is not clearly defined in contracts.

Risk allocation between QP(D), developers, contractors, and specialist consultants must be established through clear contractual provisions. Contracts should define design deliverables, monitoring obligations, what constitutes material departures, and who bears liability when site conditions differ from design assumptions.

This liability framework becomes particularly critical when QP(D) takes on specialized roles in complex projects.

Specialized QP(D) Roles and Deep Excavation Coordination

Complex projects involving underground building works demand specialized QP(D) competencies and additional layers of regulatory oversight. The coordination requirements multiply significantly when deep excavation and earth retaining structures are involved.

QP(D) for Earth Retaining and Stabilising Structures (ERSS)

ERSS design responsibilities represent one of the most demanding specializations within the QP(D) role. Under BCA’s ERSS submission requirements, different types of excavation depth thresholds trigger escalating levels of professional involvement:

• Excavation >1.5 m to ≤4 m: Basic ERSS submission by QP(D)

• Excavation >4 m to ≤6 m: QP(D) submission with accredited checker involvement required

• Excavation >6 m or classified as geotechnical building works (GBW): QP(Geo) and AC(Geo) must be engaged alongside QP(D)

For ERSS at applicable depth thresholds, geotechnical site investigation must follow GeoSS2015 standards. Borehole spacing of approximately 10–30 m along the ERSS alignment is required to capture ground and groundwater conditions. Design must comply with Eurocode 7 (SS EN 1997-1:2010 + Singapore National Annex), including checks for ultimate limit states (EQU, STR, GEO), hydraulic stability, and piping.

QP(D) must design monitoring systems specifying instrumentation types (inclinometers, piezometers, settlement markers), spacing, and control sections. Works must define alert and suspension levels for wall deflection, ground movement, and other parameters. When alert levels are exceeded, QP(D) must act-potentially requiring stop-work orders and comprehensive design review. Monthly submission of monitoring data to BCA is mandatory, with immediate notification required if suspension or work-stop thresholds are reached.

The design must also incorporate contingency measures: what happens if observed performance exceeds trigger levels, what remedial actions are available, and how the retaining wall system will be modified if site conditions differ from design assumptions. These temporary works design elements are critical for protecting adjacent structures and preventing ground loss.

Multi-QP(D) Project Coordination Protocols

Large-scale projects may require multiple QP(D) appointments across different disciplines. Joint BCA/URA circulars issued in 2023–2024 clarify when one QP(D) suffices versus when projects require multiple qualified persons or specialist QP(D) appointments-for example, demarcation between main structural elements and minor works.

Lead QP(D) responsibilities in multi-QP projects include:

• Coordinating design integration across structural, geotechnical, and building services disciplines

• Managing interfaces between QP(D) specializations to prevent gaps or overlaps

• Ensuring authority submissions present a coherent, integrated design package

• Resolving conflicts between specialist design inputs

Deep Excavation Works Coordination Requirements

During deep excavation planning, QP(D) coordination extends beyond pure design into construction stage interface management. The design must specify:

• Supervision protocols for the builder and QP(S), including checking sheet pile interlocks and gap observation procedures

• Monitoring instrumentation placement, reading frequency, and responsibility assignments

• Trigger values and the decision making framework for escalation

• Contingency protocols for when monitoring data indicates performance outside design parameters

QP(D) must produce revised designs or redesign elements if required based on site conditions and monitoring results. This construction stage responsibility in the design context ensures that the project team has clear guidance when field conditions diverge from assumptions. Reinforced concrete elements, pile cap connections, and earth retaining structure interfaces all require detailed design documentation that addresses construction sequencing.

BIM has been mandated for all public sector projects since 2014. BIM is an intelligent, data-rich digital representation of a facility that allows for clash detection before construction begins. The BCA is a key driver of BIM adoption in Singapore, and BIM enhances productivity and reduces costly rework in construction. However, temporary works such as ERSS do not need to be incorporated into the coordinated BIM model for CORENET X submissions unless they are integrated into permanent works.

These specialized coordination requirements generate some of the most common challenges QP(D) professionals face in practice.

Common QP(D) Challenges and Practical Solutions

QP(D) professionals routinely navigate complex technical, regulatory, and coordination challenges. The following represent the most frequently encountered issues and proven strategies for addressing them.

Multi-Agency Coordination Delays

Securing approvals from multiple regulatory bodies-URA, BCA, SCDF, PUB, LTA, NEA, NParks, and potentially JTC-creates sequential dependencies that can delay projects significantly.

Solution: Early engagement through pre-consultation processes with key agencies identifies potential conflicts before detailed design begins. Concept approval submissions to URA should precede detailed BCA structural plan submission. Understanding each agency’s submission requirements and review timelines allows QP(D) to sequence submissions strategically and avoid bottlenecks.

Design Integration Conflicts

Multi-disciplinary design teams-architects, structural engineers, geotechnical specialists, fire safety consultants, M&E engineers-inevitably produce design conflicts that must be resolved before submission.

Solution: Regular design team workshops and interface coordination meetings, structured around BIM coordination protocols and clash detection procedures, surface conflicts early. While industry lingo differs across disciplines, establishing shared design parameters and coordination drawings reduces miscommunication. Value engineering during the design phase optimizes project costs without sacrificing quality-it involves analyzing project functions to improve value and can reduce construction costs by 10–30%. Value engineering enhances project efficiency and performance when applied systematically.

Liability and Insurance Coverage Gaps

Professional indemnity insurance policies may not automatically cover all aspects of QP(D) engagement, particularly for alternative solutions, ERSS design, or monitoring obligations.

Solution: Comprehensive professional indemnity insurance procurement should specifically address the full scope of QP(D) services. Clear contractual liability allocation and indemnity arrangements with project stakeholders prevent disputes when issues arise. Contracts must define what constitutes material departures from approved plans, specify monitoring obligations, and clarify the QP(D)’s role in construction stage interface. Structural inspections ensure compliance with safety regulations, and Qualified Persons must supervise and inspect building works on-site-ensuring these obligations are contractually documented protects all parties.

Understanding the distinction between PE endorsement and QP submission is also essential for proper scope definition and liability management.

Conclusion and Next Steps

QP(D) is far more than a design title-it is a statutory office carrying criminal, civil, and professional liability for building control compliance in Singapore. From plan preparation and due diligence through multi-agency coordination, alternative solutions assessment, and deep excavation design, the QP role demands both technical mastery and regulatory fluency. The Building Control Act mandates compliance with safety standards, and the consequences of non compliance range from substantial fines to imprisonment and civil damages.

Immediate action steps for developers:

1. Appoint QP(D) early in the project timeline, ensuring the individual holds a valid practising certificate and appropriate specialization

2. Define contractual scope clearly, including design deliverables, monitoring obligations, and liability boundaries

3. Establish coordination protocols between QP(D), QP(S), and the broader project team before design commences

Next steps for QP(D) professionals:

1. Conduct authority pre-consultation with BCA, URA, and SCDF to identify project-specific regulatory requirements

2. Coordinate design team integration across all disciplines from the first schedule of project meetings

3. Verify compliance pathways-acceptable solutions versus alternative solutions-for each design element

4. Confirm professional indemnity insurance coverage matches the full scope of engagement

A Temporary Occupation Permit is required for building occupancy upon completion, and QP(D) must submit record structural plans (Form C3) declaring any deviations from approved plans before statutory completion can proceed. The entire lifecycle-from design through certification-falls within QP(D)’s sphere of responsibility.

Related topics worth exploring include QP(S) supervision requirements, BCA structural submission procedures, and design compliance frameworks for Singapore construction projects.

Additional Resources

• BCA guidelines for building plan submission and QP(D) submission requirements

• BCA ERSS submission requirements for deep excavation and geotechnical building works

• Professional Engineers Board registration pathways and continuing education requirements

• Singapore Construction Compliance Checklist for ensuring project approval readiness

• BCA Periodic Structural Inspection Guide for ongoing compliance obligations