CHAS — Contractors Health and Safety Assessment Scheme — is the UK's most widely accepted health and safety pre-qualification across councils, NHS trusts, housing associations, and main contractors. Four tiers (Standard, Premium, Elite, Verified Pro). Costs £200–£1,200 depending on tier and turnover. Faster and cheaper than ISO 45001 but accepted by most lower- and mid-value contracts.
What is CHAS?
CHAS (Contractors Health and Safety Assessment Scheme) is a UK-based pre-qualification scheme that assesses contractors against a standardised health and safety questionnaire. A CHAS-accredited contractor has demonstrated, through document review and (at higher tiers) on-site assessment, that they have safe systems of work, qualified competent staff, and proper risk management.
CHAS sits inside a wider category of schemes known as Safety Schemes in Procurement (SSIP) — a federation that allows mutual recognition across multiple pre-qualification schemes. If a buyer accepts SSIP-recognised accreditation, they will accept CHAS, SafeContractor, SMAS, Constructionline (above a certain tier), and a handful of others.
Unlike ISO 45001 (an international management system standard), CHAS is UK-specific and document-led. It's faster to obtain, cheaper, and accepted by the majority of UK public sector buyers for lower- and mid-value contracts.
The CHAS tiers explained
CHAS offers four membership tiers — each builds on the one below. Buyers specify the tier they need; you don't choose at random.
CHAS Standard. Document-based assessment of health and safety policies, procedures, and competence. Annual renewal. Suitable for sole traders, micro-businesses, and lower-value contracts.
CHAS Premium. Standard plus financial standing, environmental, quality, equality, and supplier diversity checks. Recognised by Common Assessment Standard (CAS) — meaning a CHAS Premium accreditation also satisfies the CAS requirements that some buyers ask for.
CHAS Elite. Premium plus on-site verification audit. The auditor visits your premises (or a work site) and checks that documented procedures are actually followed. More credibility but proportionately more cost.
CHAS Verified Pro (for sole traders). A simplified route for self-employed contractors that delivers a Common Assessment Standard equivalent at lower cost.
How to get CHAS accredited
Step 1: Choose your tier
The tier you need depends entirely on the contracts you want to win. Most local authority and housing association maintenance frameworks accept CHAS Standard. Larger framework contracts or those requiring Common Assessment Standard need CHAS Premium. ENKII shows per tender which tier is required.
Step 2: Apply online
Applications are submitted through the CHAS online portal. You upload your health and safety policy, risk assessments, training records, accident statistics, insurance certificates, and proof of competent staff (named individuals with relevant qualifications — NEBOSH, IOSH, CITB Site Safety Plus, etc.).
Step 3: Document review
A CHAS assessor reviews your submitted documents against the SSIP common assessment questionnaire. They may come back with clarifications or requests for additional evidence. Most small businesses get through document review in two to four weeks.
Step 4: On-site verification (Elite tier only)
For CHAS Elite, an assessor visits your premises after document review passes. They interview your nominated competent person, inspect documentation, and may visit a live work site. This usually takes half a day for an SME.
Step 5: Accreditation issued
Once your application passes, you receive your CHAS accreditation. It's valid for 12 months and renewable annually. Renewal is a lighter process than initial accreditation — usually just confirming nothing material has changed and updating accident statistics.
How long does CHAS take?
For an SME with existing health and safety documentation, 3–6 weeks for CHAS Standard, 6–8 weeks for CHAS Premium, 8–12 weeks for CHAS Elite. Significantly faster than ISO 45001, which is one of its main attractions.
How much does CHAS cost?
Pricing scales with the tier and your turnover band. For a small business (under £1M turnover):
- CHAS Standard: £200–£400
- CHAS Premium: £400–£700
- CHAS Elite: £700–£1,200
For businesses with higher turnover, costs scale up but stay below ISO 45001's pricing range.
Renewal is typically 60–80% of the initial cost. Across multiple years, CHAS is significantly cheaper than ISO 45001 surveillance audits — which is why it's the first-choice scheme for many SMEs whose target contracts accept it.
CHAS vs SafeContractor vs Constructionline
All three are SSIP-recognised health and safety pre-qualification schemes. Buyers will usually accept any of them as equivalent. The choice is largely about which your customers already recognise — public sector buyers tend to specify CHAS, while major contractors lean toward SafeContractor and Constructionline. Constructionline at Gold or Platinum level also covers commercial and financial standing beyond just H&S, which CHAS doesn't.
How ENKII helps with CHAS
ENKII identifies which tenders accept CHAS as an alternative to ISO 45001 and at which tier. For SMEs whose target contracts only need CHAS, this avoids unnecessary spend on the more expensive ISO certification.
Once accredited, add CHAS to your ENKII profile with your tier and renewal date. ENKII tracks the renewal and reminds you before lapse.
Frequently asked questions
Do I need CHAS if I already have ISO 45001?
Usually no — ISO 45001 covers everything CHAS does and more. Some buyers explicitly require CHAS as well, but they're a minority. The main reason to hold both is time-pressure — if a tender closes before you can complete ISO 45001 but accepts CHAS, it's worth getting CHAS as a bridge.
What's a "nominated competent person"?
CHAS requires a named individual responsible for health and safety, with a relevant qualification (NEBOSH General Certificate is the most common, with IOSH and CITB alternatives accepted). They don't have to be a full-time H&S manager — many SMEs have a director or senior staff member who holds the qualification alongside other duties.
How does CHAS compare to Constructionline?
Both are pre-qualification schemes. CHAS is health-and-safety led. Constructionline is broader — covering commercial standing, financial information, and quality alongside H&S, with tiered membership from Bronze through Platinum. For construction sector procurement specifically, Constructionline tends to be more commonly specified. See our Constructionline guide for the detail.
Is CHAS Verified Pro right for me as a sole trader?
If you're a self-employed contractor (sole trader, no PAYE staff) bidding for work that requires CHAS, the Verified Pro route is significantly cheaper and faster than CHAS Standard while satisfying the Common Assessment Standard requirement most buyers ask for. Costs typically £150–£250.