--- title: "WP1140 - T5D Design Consultant" ocid: "ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d" canonical_url: "https://d3tenders.com/contract/?ocid=ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d" markdown_url: "https://d3tenders.com/contract/ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d.md" json_url: "https://d3tenders.com/contract/ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d.json" source: "Contracts Finder" current_stage: "Tender" buyer: "COSTAIN LIMITED (H7-HEATHROW)" published: "2026-06-02" --- # WP1140 - T5D Design Consultant Buyer: COSTAIN LIMITED (H7-HEATHROW) Current stage: Tender OCID: ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d [View canonical contract page](https://d3tenders.com/contract/?ocid=ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d) [Download OCDS JSON](https://d3tenders.com/contract/ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d.json) ## Summary The procurement process, initiated by Costain Limited (H7-Heathrow), involves the provision of engineering design services for the WP1140 - T5D Design Consultant project, located in London, United Kingdom. This tender falls under the “Engineering design services” industry category with a CPV code of 71320000. The objective of the project is to replace the four attenuators in the T5D Shaft at Heathrow Rail Tunnels to enhance safety and reduce maintenance needs. The tender is currently at the Tender stage with a submission deadline of 9th June 2026. The project is valued between £2,500,000 and £5,000,000, with the contract period expected to run from 7th August 2026 to 1st December 2026. The procurement process is suitable for SMEs and VCSEs, providing a significant opportunity for growth in this sector. This tender presents valuable opportunities for businesses specialising in underground rail network ventilation resilience, particularly those with expertise in airflow modelling and compliance with operational rail network constraints. With the requirement for a Ventilation Resilience Report, it supports businesses that have capabilities in engineering design services and an understanding of complex mechanical, electrical, and plumbing (MEP) systems. Additionally, firms with experience in executing projects in busy urban environments like London, especially within the constraints of operational rail networks, would find this tender especially appealing, potentially leading to long-term partnerships and increased market presence. ## Notice The T5D Rail-tunnel Ventilation Shaft is located adjacent to T5D at its North and can be accessed from the bottom (Level 6) via the trackside of the HEX tunnel or from the top (level 7) via Airside. The objective is to replace the four attenuators in the T5D Shaft because they are at their end of life. The renewal of the T5D attenuators aims to reduce the risk of debris entering fans, tunnels and station, prevent the fans from failing in any fire scenario and provide ventilation and smoke clearance for the Heathrow Rail Tunnels. This improves safety conditions within Heathrow Rail Tunnels and improves resilience of systems. In addition, less maintenance and repair are required for the attenuator. Each attenuator is formed of four quadrants weighing around 1160 kg. Review MEP systems along the airflow and advise replacement/modification to bring them up to compliance. Surveys will be carried out by others (Employed by the Client) under the direction of the Design Consultant Item Question Q1 Do you have experience with Underground rail network ventilation resilience? Requirement: Ventilation Resilience Report required for the HAL Rail underground network. Q2 What capability do you have of air flow modeling for fans / attenuators etc.? Requirement: Model the existing configuration with one fan operating, and both fans operating and then repeat the modelling with shaft sub divided to allow one set of attenuators to be replaced while the other is operational. Q3 What capability do you have of understanding the requirements for specifying replacement attenuators etc., Specifically considering the constraints of an operational rail network? Note: - RIBA 5 onwards including construction is excluded. ## Key Details | Field | Value | | --- | --- | | Publication source | Contracts Finder | | Latest notice | https://www.contractsfinder.service.gov.uk/Notice/2a1ded63-c1d7-4984-9540-4dd819838020 | | Notice type | Tender Notice | | Procurement type | Standard | | Procurement category | Services | | Procurement method | Not Specified | | Procurement method details | Not specified | | Tender suitability | SME, VCSE | | Awardee scale | Not specified | | All stages | Tender | ## Dates | Field | Value | | --- | --- | | Publication date | 2 Jun 2026 | | Submission deadline | 9 Jun 2026 | | Future notice date | Not specified | | Award date | Not specified | | Contract period | 6 Aug 2026 - 1 Dec 2026 | | Recurrence | Not specified | ## Values | Field | Value | | --- | --- | | Tender value | £5,000,000 | | Lots value | Not specified | | Awards value | Not specified | | Contracts value | Not specified | ## Status | Field | Value | | --- | --- | | Tender status | Active | | Lots status | Not specified | | Awards status | Not specified | | Contracts status | Not specified | ## Buyer | Field | Value | | --- | --- | | Main buyer | COSTAIN LIMITED (H7-HEATHROW) | | Locality | MAIDENHEAD | | Post town | Slough | | Postcode | SL6 4UB | | Country | England | | ITL 1 | TLJ South East (England) | | ITL 2 | TLJ1 Berkshire, Buckinghamshire and Oxfordshire | | ITL 3 | TLJ15 Berkshire East | | Local authority | Windsor and Maidenhead | | Electoral ward | Oldfield | | Westminster constituency | Maidenhead | | Delivery location | TLI London | ## CPV Codes ### Divisions - 71 - Architectural, construction, engineering and inspection services ### Codes - 71320000 - Engineering design services ## Release History - 2 Jun 2026 at 09:20 - Tender - Tender Notice - https://www.contractsfinder.service.gov.uk/Notice/2a1ded63-c1d7-4984-9540-4dd819838020 ## Documents - https://www.contractsfinder.service.gov.uk/Notice/2a1ded63-c1d7-4984-9540-4dd819838020 2nd June 2026 - Opportunity notice on Contracts Finder - https://www.competefor.com/business/viewOpportunityDetailsSupplier.html?id=113536291 Please follow this link to view the notice. ## Provenance This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-b5fd17-abb75190-6054-4f95-b2a7-26ec9ecfbe8d.json.