UK Public Sector Contracts & Tenders

Expression of Interest T5D MEP Subcontractor T5D Attenuator Overhaul (Survey / RIBA 4iii) Scope 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 in 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 MEP Subcontractor under the direction of the Design Consultant (Employed by the Client). Item Question Q1 What capability do you have of understanding the requirements for replacing attenuators etc., considering the constraints of an operational rail network? Q2 What capability do you have of carrying out a survey of the T5D Shaft during non-operational hours to provide all the information required to complete the RIBA 4ii design by the Design Consultant and the RIBA 4iii by the MEP Subcontractor? • M&E Services within the air path • Fan and Attenuator • Structure Note: - RIBA 5 onwards including construction is excluded.

Expression of Interest Tunnel Vent, Fans and Fan Drives MEP Subcontractor Tunnel Vent, Fans and Fan Drives (Survey and RIBA 4) Scope The objective of this scope is to replace components that form part of the ventilation system at Central Terminal Area (CTA) North and South, Terminal 4 North and South and Sipson Farm, that are at their end of life. The components of concern are Fan Drives and Low Voltage Air Circuit Breakers. It is proposed that all components for the 8 No. existing Variable Speed Drives (VSD) which are close to their designed lifetime are to be replaced, together with the panel. It is proposed that all components for the 5 No. existing Direct On-Line (DOL) starters which are close to their designed lifetime are to be replaced, together with the panel are replaced with VSD's. The VSDs are to be connected to the Tunnel Control System (TCS). The incoming air circuit breakers (ACB's) and the low voltage protection devices (MCCB/MCB's) within the existing switch gear will be replaced with new devices. Where the impact is significant, this may lead to replacing the entire LV switchgear and the DOL panels for the associated equipment. New lighting will be provided by energy-efficient LED luminaires, as the existing lighting system is in poor condition. As part of small power provision, 240V socket outlet assemblies shall be provided near damper units. The existing junction boxes and cable termination boxes need to be replaced with new equipment. Item Question Q1 What capability do you have of understanding the requirements for replacing Electrical infrastructure etc., Specifically considering the constraints of an operational rail network? Q2 What capability do you have of carrying out a survey of the 5 ventilation buildings non-operational hours to provide all the information required to complete the RIBA 4 design? Note: - RIBA 5 onwards including construction is excluded.

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.