One Leadenhall, The Work — pre-commission cleaning, disinfection & commissioning.
A premium flexible-workspace fit-out across Levels 22 and 23 of One Leadenhall, a landmark tower in the City of London. Appointed by M&E contractor Mectric Solutions, BWS delivered the full water-side scope — BG29 pre-commission cleaning of the heating and chilled systems, BS8558 domestic disinfection, and water- and air-side commissioning through to certified handover.
Two floors, twenty-two storeys up.
One Leadenhall is one of the City of London's newest landmark towers. The Work Project — a premium flexible-workspace operator — took Levels 22 and 23 for a high-specification fit-out, served by their own dedicated heating, chilled and domestic water systems split across a north and south core on each floor.
BWS was appointed by the mechanical contractor, Mectric Solutions, to deliver the complete water-side package: getting four new closed systems clean and treated, the domestic installation disinfected and certified, and the water and ventilation systems balanced to design — all from Level 22 of a live, occupied City tower.
Scope at a glance
- Pre-commission cleaning of CHW systems — L22 & L23
- Pre-commission cleaning of LTHW systems — L22 & L23
- Alkaline chemical clean, inhibitor & condensed biocide wash
- 16 × BSRIA Table 4 bacterial & chemistry sample suites
- Closed-system remediation & re-sampling to BG50 targets
- BS8558 disinfection of the domestic water installation
- UKAS-accredited Legionella & potable sampling
- Water systems commissioning & balancing — L22 & L23
- Ventilation commissioning — L22 & L23
- Effluent discharge consent obtained before flushing
Five streams, one accountable team.
BG29 Pre-Commission Cleaning
Dynamic flushing of the four CHW and LTHW closed systems across L22 and L23 to BSRIA BG29:2021, followed by an alkaline chemical clean, a condensed biocide wash and inhibitor passivation. Flushing velocities achieved on the system pumps, with line-size bypasses across the FCUs.
Closed-System Sampling
Sixteen BSRIA Table 4 sample suites taken to BS8552:2012 across the four systems — turbidity, dissolved iron and copper, total viable counts, 5-day sulphate-reducing bacteria and inhibitor residual, all checked against BG50:2020 acceptance targets.
Remediation & Re-Sampling
Where first-pass results on the L22 systems came back outside specification, BWS ran a targeted remediation programme — additional cleaning, re-dosing and circulation — then re-sampled to bring the chemistry and microbiology back inside BG50 targets before sign-off. Documented in full in the remediation reports.
BS8558 Domestic Disinfection
Chlorination of the new domestic hot and cold water installation to BS8558 and PD 855468:2015, with UKAS-accredited Legionella and potable sampling following disinfection. Disinfection certificates issued for both the October and December works.
Water & Ventilation Commissioning
Hydraulic balancing of the CHW and LTHW networks to design flow rates, plus supply and extract ventilation commissioning across both floors — AHU and FCU airflows measured and proportionally regulated to current CIBSE commissioning codes, with witnessed data sheets.
Evidence Pack & Certification
Full evidence pack issued for handover — BG29 acceptance chemistry, BG50 sample trackers, remediation reports, BS8558 disinfection certificates, UKAS lab analysis and commissioning data sheets — delivered within 14 days of completion.
The finished workspace, twenty-two storeys up.
The water-side work sits behind two floors of premium flexible workspace — from the arrival lobby and reception through the lounges, pantry and meeting suites — all served by the heating, chilled and domestic systems BWS cleaned, disinfected and commissioned. Photography courtesy of The Work Project.
The compliance map for One Leadenhall.
The headline standard for getting the four new closed systems clean before handover — dynamic flush, chemical clean, passivation and sample evidence.
The chemistry standard the acceptance samples — and the remediation re-samples — were judged against.
The sampling methodology for the sixteen BSRIA Table 4 closed-system sample suites.
Code of practice the domestic chlorination and certification were carried out under.
The published guidance for disinfection of new pipework, applied alongside BS8558 and BS EN 805.
The technical codes for balancing the hydronic and ventilation systems across both floors.
Clean, chlorinated, balanced — and back in spec.
All four closed systems were handed over within BG50 targets — including the L22 systems that needed remediation, which were re-cleaned, re-dosed and re-sampled to a clean pass. The domestic installation was chlorinated and certified, and the water and ventilation systems balanced to design across both floors.
Mectric Solutions and The Work Project received a complete BWS evidence pack inside the agreed window — acceptance chemistry, remediation records, disinfection certificates, UKAS lab analysis and commissioning data sheets. A clean start for two floors of premium workspace in the City.
What was delivered
- 4 closed systems within BG50 acceptance targets
- Remediation reports — L22 North & South
- 16 BSRIA Table 4 sample suites (BS8552)
- BS8558 disinfection certificates × 2
- UKAS-accredited Legionella & potable analysis
- Water commissioning & balancing data — L22 & L23
- Ventilation commissioning records — L22 & L23
- Full evidence pack within 14 days of completion