On a December evening in Sydney, a section of the Orora Botany Paper Mill’s waste paper storage area caught fire.
The fuel source was large bales of waste cardboard having been stockpiled for future re-cycling. The heart of the fire was located in an extremely difficult area for Fire & Rescue NSW to access; but fortunately McMahon Services were able to assist with rapid response by using a site-based excavator to break up the burning stockpiles. The Pc220 excavator was used to literally ramp up onto the burning stockpiles and separate them as the overhead snorkel water delivery systems drenched the exposed flame.
This process allowed Fire & Rescue NSW to control the blaze much sooner and continued for the next two days, often during the night as hot spots re-ignited. Whilst this exercise certainly helped contain the initial out break it could not prevent the spreading of the fire to the redundant B7 Paper Mill. This no longer in production building incurred major damage to the roof section and internal plant and infrastructure to the upper level machine floor.
McMahon Services were requested to return to site just after Christmas to carry out the removal of sections of fire damaged roof sheeting to reduce the risk of loose debris becoming airborne during possible inclement weather.
This task was carried out by the manual removal of sheeting by personnel working from a crane suspended aerial work platform. The removal process was challenging due to the restriction of “Hot Works” because of the possible risk of re-ignition.
When the structure was deemed safe enough for controlled entry, the internal fire damage was inspected. During this inspection it was discovered that large sections of steam pipework, having been insulated with friable asbestos, whilst contained within an exclusion zone, were in an exposed condition.
Consequently Orora issued a contract to McMahon Services for the safe asbestos pipe removal from the B7 Paper Mill, in accordance with NSW legislative requirements.
Further evaluation of the internal pipework showed lengths that had been partially cleaned of the friable insulation and recoated with a synthetic mineral fibre (SMF) by previous contractors.
McMahon Services made the decision to include the removal of all lengths of pipe insulation to negate the risk of inadvertently leaving hazardous materials within the exclusion zone in areas outside of the scope of works.
The methodology required the installation of negative air working environments that was achieved by encapsulation of the removal areas and installing HEPA filtered exhaust fans to draw a positive air flow in through the “Haz-Mat” decontamination units and out through the filtered fan units.
The internal pipe removal was located on two levels at heights of up to six metres requiring safe access and working platforms. This was primarily achieved by using a specialist scaffold contractor to supply and erect quick stage scaffolding. This scaffold was also utilised as the structural framework for some area encapsulations.
Where it was not practical to erect a negative air enclosure, a “Glove Bag” methodology was used to remove the insulation from full length and part length sections of the pipe work. This method was predominately used for suspended external runs and effectively allowed for future “Hot Work” separation and sectional crane lowering.
The nature of a paper mill waste paper storage yard posed constant problems when using an ignition source, such as high temperature cutting. This called for an agreed combination of preapproved methodologies between the client’s Safety Team & McMahon Services’ site project team. No outbreak of fire resulted from these works.
External lengths of insulated pipe were to be removed that were suspended within a high-level service gantry. The solution was to separate the asbestos insulated pipes utilising the “Glove Bag” method and deconstruct the gantry into manageable sections for hoisting to ground level.
This required duel crane lifts, with the loads averaging 20 tonnes per section. Extensive traffic control was required due to the work zone intersecting with the operating waste paper delivery route.
These lifts were carried out over a two week period without any adverse impact to the client’s daily operations. Extensive high temperature cutting was required for the deconstruction, both for the initial gantry configuration and for further downsizing at ground level.
