Thank you for your enquiry, assuming the steels are in an internal, dry environment and have a minimum wall thickness of 4mm I calculate you have approximately 1.8m² of surface area to coat. For this you would require 4.5 litres of Zeroflame Aquasteel WB+ to achieve 30min protection - https://www.rawlinspaints.com/products/272-zeroflame-aquasteel-wb.html 

Assuming the steel is currently just suitably primed, once the Zeroflame Aquasteel WB+ has been applied, if the steel is to remain visible you should finish with Zeroflame Aquasteel WB+ Finish in the colour and finish of your choice - https://www.rawlinspaints.com/products/851-zeroflame-aquasteel-wb-topcoat.html - just 2.5 litres of this would be required. 

Upon completion you simply peel the label of the basecoat tin and complete the certificate application form. Once submitted a certificate will be returned to you and this is what you can give to the client/authority. 

Delivery/Availability

3 – 5 Working Days          -              FREE

2 – 3 Working Days          -              £8.00 + VAT

Next Working Day            -              £15.00 + VAT