Case Study: SMART Tunnel, Kuala Lumpur

How KSM Phoenix Engineered Noise and Vibration Control for One of the World's Greatest Tunnels

Location
Kuala Lumpur, Malaysia

Business
KSM Phoenix Noise Control

Year
2007

Scope
Tunnel Ventilation Attenuators — Design, Fabrication & Delivery

A view inside a tunnel with a curved ceiling, illuminated by yellowish lights. The road has a double yellow line in the center, with a few cars driving through toward the dark exit of the tunnel.

Summary

The Stormwater Management and Road Tunnel (SMART Tunnel) is one of Malaysia's most ambitious infrastructure achievements — a 9.7km dual-purpose tunnel built to combat flooding and traffic congestion in the heart of Kuala Lumpur. Completed in 2007 and later named one of CNN's World's Greatest Tunnels, the project presented a unique noise and vibration challenge that demanded precision engineering under tight deadlines.

KSM Phoenix was engaged to design, fabricate, and deliver the tunnel's ventilation attenuators — custom-engineered systems that reduce noise from ventilation shafts to safe and acceptable levels for surrounding residential and commercial areas. It remains one of the most technically demanding noise control projects undertaken by our team.

The Challenge

Despite its innovative design, the SMART Tunnel's North and South ventilation shafts generated significant noise and pressure that posed health and safety risks to the surrounding community. Compliance with strict noise and health standards was non-negotiable — but the project came with equally strict deadlines and volatile technical requirements.

Our scope was to design, manufacture, supply, and deliver tunnel ventilation attenuators that would reduce noise to acceptable levels without compromising the tunnel's structural integrity or airflow performance.

The Strategy

Our team of engineers, drafters, and fabricators mobilized swiftly. Working within our private ISO-certified test laboratory and fabrication yard, our team ran multiple Factory Acceptance Tests (FATs) under strict ISO 7235 procedures — covering insertion loss, flow noise, and total pressure loss.

A critical design requirement was that attenuators must withstand extreme moisture conditions after flood events. We deliberately designed and tested each unit to handle post-flood operations — a capability our in-house testing facility was specifically equipped to validate.

We ensured the project exceeded expectations through:

  • Rigorous ISO-compliant fabrication and quality control procedures throughout production

  • Acoustics laboratory measurements for duct silencers and air terminal units

  • Safe and secured pre-delivery storage in controlled conditions to prevent weather and humidity damage

  • Efficient coordination with third-party acoustic splitter installers on-site

  • Around-the-clock stakeholder communication ensuring all deadlines were met

The Results

All attenuators met the noise and pressure drop criteria specified, and were delivered and installed punctually. The SMART Tunnel has since operated continuously, diverting stormwater over 44 times and serving more than 30,000 vehicles daily.

44+Flood diversion events since commissioning
30,000Vehicles per day served by the tunnel
9.7kmTunnel length — one of the world's longest dual-purpose tunnels
#1Listed among CNN's World's Greatest Tunnels (2016)


Fun fact: The SMART Tunnel was listed as one of the World's Greatest Tunnels by CNN in 2016 and has diverted stormwater over 44 times, protecting Kuala Lumpur's city center from major flooding events.

References

1. https://edition.cnn.com/travel/article/great-tunnels-2016/index.html

2. https://www.roadtraffic-technology.com/projects/smart/