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Laser cleaning causes less disruption Visable effect of laser cleaning Laser cleaning of ancient stone work Tube Tech cleaning of ancient stone work Morning cleaning information

Tube Tech removes 140 years of building grime

Removing over 140 years worth of grime from any building would be a challenge to most cleaning contractors. Add to this the fact that the building is a Grade 1 listed building, closely monitored by both English Heritage and the Victorian Society, and you have just the kind of challenge which Tube Tech International Ltd love to take on. The towns museum was significant in the development of 19th century architecture, the history of its University, and in the study of science in England. The result is as spectacular today as when it was first opened.

A UK based international petrochemical company shipped a severely fouled styrene polymer bundle to Tube Tech in order to minimise costs as they own an identical changeover replacement already. A production anomaly led to a thick, hard, brittle deposit forming on the shell side of the bundle and also severe bend blockages in tubes. Our challenge was develop a method to unblock polymer from the U Bends within a small 2m square footprint in front of the exchanger so in future it could be cleaned in-situ, saving on crane costs, scaffolding, damage, gaskets, bolts and third party costs.  A triple lance feeding mechanism was modified to allow lances to negotiate and unblock the every U-Tube. The client correctly pointed out that it was a pointless exercise if only the straight section was cleaned and the hairpin bend left blocked. By using Tube Tech’s globally patented Plate and Shell Jet every last particle of fused polymer was removed, even from deep inside the bundle. All the tubes were unblocked, descaled and polished using the modified triple lancing method.


  • The museum is visited by over 300 000 people per year.
  • This volume of human traffic plus other environmental pollutants had caused a build up of dirt upon the stone work of the viewing galleries.
  • The buildings administrators wished to have the stone work cleaned back to its natural state.
  • The area to be cleaned included the walls and columns of two 40m galleries and due to funding restrictions the time frame for the work to be completed was 12 days.
  • It was crucial that the fragility of the stone work, some of which could be marked with the scratch of a fingernail, was protected and that the other surfaces to which the contractor might come into contact with, including the highly detailed tiled floor, were also protected.
  • The work had to be completed during the buildings traditional opening hours, the building would continue to be open to the public and priceless exhibits would be in place in the area directly below and around the cleaning operation.
  • In the past a member of the museums maintenance team had spent 3 years with hot water and a brush cleaning one side of the galleries stone work.
  • The museum had also previously used a laser cleaning contractor who, using two laser systems, 8 hours per day, seven days a week, took in excess of 3 months to clean two 40m sections of the gallery.


  • Due to the museums time restrictions Tube Tech used a 50 and 70mm laser which is far larger than traditional laser cleaning equipment.
  • This meant that a small team could clean a larger area far more quickly.
  • Always highly aware of safety issues Tube Tech ensured that no member of the public was able to look directly at the laser as this could have damaged their vision.
  • Lasers have been successfully used across the world to clean monuments while preserving patina, fine surface details and important surface coatings.
  • Laser cleaning works by ablation: the coating layer is removed as it absorbs the focused laser line.
  • Very powerful but short laser pulses have little thermal influence on the base material.
  • The blank base material reflects laser radiation, stopping the ablation process.
  • With the correct laser parameter and best wavelength, the profile of the stone cannot be damaged and the dirt removed is vapourised (ablation by sublimation) and removed by thermally-induced pressure.
  • Tube Tech also used their specialist access scaffold tower which featured a cantilever so they could work on the front leading edge.
  • The Tube Tech team ensured that rubber matting was used underneath the laser equipment in order to protect the delicate tiled floor of the museum.
  • Constant communication with the client ensured that the priorities of the museum, which did alter during the course of the contract, were met and that the client was fully aware of Tube Techs progress throughout the contract.
  • Tube Tech cleaned a full 40m gallery in 10 days (almost 4 x faster than previous laser technology) and met all of the safety, security, conservation and protection issues as specified by the client.

Tube Tech Comment

Mike Watson, Managing & Technical Director: “Working on a cleaning contract surrounded by priceless exhibits was a first for our team. It was exactly the kind of challenging job which Tube Tech is known and respected for and seeing the difference on the stone work after the laser cleaning was highly satisfying. The use of our larger laser within this fragile environment was a perfect choice as there was no noise emission, the vaporised waste was vacuumed away immediately and there was no interruption to the museums activities.”

For more information or to discuss your cleaning challenge call us on +44 1268 786999 or e-mail, alternatively click here to fill out our contact form.

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