13 September 2017

Recently, an air conditioning contractor discovered some asbestos containing material [ACM], adjacent to the North Riser air conditioning duct at 55 Swanston Street, Melbourne, whilst investigating a water leak in the ceiling cavity on Level 8.

Consequently, we approached a multitude of asbestos and hygiene consultants to enquire how best to investigate the extent of the asbestos. We wanted to know, without any doubt, whether the asbestos containing woven rope, that had been used as a fire retardant adjacent to the riser, had been used inside the riser as well. The professionals were all convinced it hadn't, but no-one was able or willing to categorically confirm their hunch, and as such, our journey for clarity began.

Prensa, GBAR, EP Risk Management, National Drones and Spectrol all became part of the investigative process.

The set task was not an easy one. 55 Swanston Street has the busiest lift shafts in all of Melbourne! The first logical step was to plan a weekend investigation, as this would minimise disruption and any potential alarm amongst the 42 commercial tenants and their visitors/guests.

Intrusive investigation to determine the exact nature and whereabouts of ACM, requires a lot of time and effort, due to the very unique, specialised and regulatory setup procedure.

To fulfil the contractual obligation of the scope of works, an entire level would need to be sealed off for a period of 60 hours. During this time, GBAR would quarantine the entire floor, seal off the stairwell, assemble specialised showers and plumb them into the toilet block, erect timber-framed enclosures masked with plastic sheets before establishing a negative pressure air chamber within which the investigative work would be conducted. To ensure GBAR followed the stipulated protocol, Prensa would conduct an independent real-time review of GBAR’s setup and work procedures, whilst simultaneously monitoring the air quality of the sealed level, throughout the duration.

As is the case with any remedial asbestos works - statutory requirements compelled us to notify all adjacent building owners and tenants of our proposed asbestos remedial works. Additional signage advising all tenants and visitors of the asbestos works in progress was also required.

Upon further brainstorming for alternative solutions and much thought and deliberation, GBAR suggested the possibility of using a drone to investigate the internal membrane of the North Riser. Enter EP Risk Management and National Drones.

Up until this point, GBAR and Prensa's combined costing to perform a 60-hour intrusive investigation on a single level stood at $31,000.00. Comparatively, the cost for using National Drones and having EP Risk Management partake in the exercise prior to compiling an Executive Report was $3,630.00.

EP Risk Management are frequent users of unmanned aviation vehicle [drone] technology in a variety of applications. National Drones provided this service and upon visiting 55 Swanston Street, Mr Vic Thomson confirmed that they [National Drones] had never conducted an internal duct inspection before. Our investigation, if it were completed successfully, would set a precedent for a new service vertical for National Drones.

National Drones and EP Risk Management investigated the North Riser from the plant room access door, as best they could. Given the confined space, depth of the riser [almost 40m], absence of lighting and inability to judge whether we could control the drone safely, all added to the risk equation of the intended scope of work.

Vic knew he wouldn’t be able to fly the drone within the riser. We would simply be using the drone as a remote lighting and camera pod, which we would manually lower into the riser by rope. Vic planned and prepared for the event meticulously, labelling the abseiling rope every three and ten metres and padding the drone with a swimming pool noodle for protection.

In early August, National Drone history was made! We anchored the prepped drone via a carabiner to the abseiling rope and carefully lowered it into the abyss, operating the remote camera to capture images of any areas that required further scrutiny.

At the end of four hours, 22 images of the North Riser’s internal membrane were captured. These images were sent to EP Risk Management for detailed analysis that resulted in an Executive Report comprising the following statements –

1. The purpose of the inspection was to determine whether “the identified asbestos containing material (ACM) that was identified in site areas adjacent to riser, was not present in the riser, or did not protrude into the riser, as the presence of ACM in the riser would constitute a health risk for building occupants and visitors”; and

2. No ACM rope, or other material considered potential ACM were identified in the North Riser of the building’s air conditioning.

National Drones considered the investigation a resounding success and now promote such inspections as a “valuable tool that is quick to deploy and offers an outcome in an efficient and cost effective manner”.

Having been hopeful that the inspection would confirm the absence of friable asbestos containing woven rope inside the North Riser made the final verdict all the more sweeter.

From a price and ease of operation perspective, we would certainly investigate the use of drone technology for all future inspection and/or planning works.