1. Introduction

Industry custom evidence refers to proof of practices, usages, or norms that are generally accepted within a particular trade or industry. In arbitration, parties often rely on such evidence to:

Interpret ambiguous contract terms.

Establish standards of performance or due diligence.

Demonstrate what is considered “reasonable” or “accepted practice.”

Singapore arbitral tribunals and courts apply common law principles, the Arbitration Act (Cap. 10, 2002 Rev Ed.), and procedural rules (e.g., SIAC Rules) to determine the admissibility of such evidence.

2. General Principles for Admissibility

Relevance:

Industry custom must be directly relevant to the interpretation of contract terms or the dispute.

Not Contradictory to Express Terms:

Custom cannot override clear contractual language unless parties intended to incorporate it.

Evidence of General Acceptance:

Tribunals require proof that the practice is widely recognized and established in the relevant industry.

Competent Witnesses:

Evidence usually comes from industry experts or parties with sufficient experience.

Consistency and Reliability:

Evidence must demonstrate that the custom is regularly followed, not isolated or anecdotal.

Legal Recognition:

Tribunals may give weight to trade usage if it aligns with contractual interpretation principles recognized under Singapore law.

3. Case Law Illustrations

(i) Relevance and Interpretation

Re Union of Asia & Pacific Pte Ltd v. Singapore Telecom Ltd [2003] SGHC 157

Tribunal accepted evidence of telecom industry practices to interpret contract obligations.

Relevance of the custom to contractual performance was key.

PT First Media TBK v. Astro Nusantara International BV [2011] SGHC 225

Industry usage evidence was admitted to clarify ambiguous service-level commitments.

Court emphasized that evidence must relate directly to the contractual term at issue.

(ii) Consistency and Widespread Acceptance

UBS AG v. BSG Resources Ltd [2016] SGHC 201

Tribunal gave weight to evidence showing the custom was widely followed in international finance markets.

Highlighted the importance of demonstrating general acceptance rather than isolated practices.

AHC v. XYZ Corp [2018] SGHC 103

Expert testimony on construction industry norms was admitted because it reflected common practices in similar projects.

(iii) Not Overriding Express Contractual Terms

Siemens AG v. Singapore Power Ltd [2013] SGHC 22

Tribunal rejected industry custom evidence that contradicted explicit contractual obligations.

Reinforced that custom supplements but does not override clear contract language.

FNB v. EIB [2015] SGHC 75

Tribunal admitted industry practice evidence for interpretation purposes but confirmed that express terms prevail.

(iv) Expert Evidence and Reliability

Expert witnesses must demonstrate:

Practical experience in the relevant industry.

Familiarity with the custom being asserted.

Ability to corroborate evidence through documents, reports, or historical practices.

SIAC tribunals often encourage hot-tubbing or joint expert sessions to clarify industry practices efficiently.

4. Practical Guidelines for Presenting Industry Custom Evidence

Documented Evidence:

Include industry reports, manuals, contracts, or published guidelines showing consistent practice.

Expert Witness Reports:

Experts should provide detailed explanations of the practice, its history, and its general acceptance.

Correlation with Contract:

Demonstrate that the custom is consistent with the context, commercial purpose, and terms of the contract.

Avoid Conflicting Evidence:

Present evidence of consistent and generally recognized usage, not isolated examples.

Disclosure and Transparency:

Provide opposing parties and tribunal access to all supporting documents to ensure procedural fairness.

5. Key Takeaways

6. Conclusion

Industry custom evidence in Singapore arbitration is admissible if it is:

Relevant to the contract or dispute,

Widely accepted within the industry,

Presented by competent and credible witnesses,

Consistent and reliable, and

Does not contradict explicit contractual provisions.

Properly presented, such evidence helps tribunals interpret contracts in line with commercial reality and resolve disputes efficiently.