Knowledge base › Evidence and declarations
What the law says about certificates such as ISO 9001, VCA and the CO2 Performance Ladder, and when other evidence must be accepted.
Checked on 15-09-2026
If a contracting authority asks for a certificate showing that you meet certain quality standards, it refers to quality assurance schemes based on European standards and certified by accredited certification bodies (article 2.96 of the Dutch Public Procurement Act 2012). ISO 9001 is a well-known standard for quality management. A similar rule applies to environmental management, with reference to the European EMAS scheme or other recognised standards (article 2.97).
Both articles give you a right to offer equivalent evidence. The authority accepts equivalent certificates from bodies in other member states. It also accepts other evidence of equivalent measures if you could not obtain the requested certificate within the time limit for reasons not attributable to you, provided you show that your measures meet the standard. According to PIANOo the same applies to labels: the authority accepts equivalent labels and, under the same condition, other appropriate means of proof such as a technical dossier.
VCA is the safety, health and environment checklist for contractors and is managed by SSVV, a collaboration of 26 industry associations. There is a difference between the company certificate, which demonstrates the organisation's safety management, and personal diplomas such as B-VCA and VOL-VCA for individual workers. Read carefully which of the two a tender asks for.
The CO2 Performance Ladder (CO2-Prestatieladder) is managed by the Foundation for Climate-Friendly Procurement and Business (SKAO). Contracting authorities can use the ladder as an award criterion under the best price-quality ratio: a bidder then receives a notional discount or points matching its ambition level.
What this means for you: in every tender, check whether a certificate is a hard requirement or earns an award advantage. Obtaining a certificate takes time, so start in good time if you intend to tender regularly in your sector. If you do not hold the requested certificate but demonstrably work to the same standard, ask in the question round which equivalent evidence the authority accepts.
These articles explain how public tendering works; they are not legal advice. If you are unsure about a specific tender, ask your question through the clarification round or consult a lawyer.
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