Friday, August 14, 2015

Steam locomotive 924 insulation removal

Locomotive 924 is a six-coupled, former Northern Pacific locomotive.  It is held in the collection of the Northwest Railway Museum and beginning in November 2014 rehabilitation work has been underway.  The objective is to return the 924 to its former glory and operate it on the Museum's railway between Snoqualmie Falls and North Bend. 

924 ready for insulation removal
Urethane foam was used to seal weak
areas until the removal project was
ready to begin.
Since the fateful day last November when the locomotive was pushed into the Conservation and Restoration Center, the boiler interior has been stripped of tubes and scale, the Form 4 engineering package begun (regulatory requirement for operating a steam locomotive), new firebox side sheets fabricated and welded in place, a new all riveted tender cistern fabricated, the tender frame rehabilitated for service, and tank installed on the frame.  However, a major hurdle for the completion of the boiler work remained the locomotive's jacketing and insulation.  In order to complete the Form 4 process, the exterior of the boiler had to be stripped for visual inspection, and the final ultrasonic thickness data collected.  

Director Anderson and
Curator Pappas wore
elaborate protective
equipment.
Preliminary testing determined that the insulating material was a form of asbestos, commonly used for locomotive boiler insulation, but now found to be harmful to human respiratory systems, causing malignant cancers, formation of plaques that inhibit lung function, and a host of other nasty, potentially life-ending conditions. Needless to say, the work of removing this material needed to be performed in a safe manner for everyone involved.  Hiring a remediation contractor is quite expensive, and it was the suggestion of volunteer Zeb Darrah to obtain the necessary training and certification to legally conduct the remediation in house.  He recommended several potential training programs, and did the majority of the preliminary fact finding for the legalities of doing this work in house. In preparation for this museum director Richard Anderson and curator Efstathios Pappas received training from Argus Pacific, a private firm that specializes in hazardous material handling training.  

Edwin from Global Asbestos
Contractors checks verifies
the entry door seal on the
containment structure.
In early August, remediation work began working with Global Asbestos Abatement, a licensed asbestos contractor.  By partnering with this firm, valuable advice and experience was available to the team, but perhaps more importantly the necessary equipment to complete the job safely and effectively.  

A double-wall containment structure
was built over locomotive 924.
Over the course of three days, the mandated double wall containment was constructed of polyethylene sheeting, and taped so as to be air tight to a minimum of -.018 inches of mercury with HEPA negative air machines running.  A three stage decontamination chamber was built and attached to the front of the enclosure, and pre-abatement samples taken so as to demonstrate a clean and safe working environment, and provide comparison for the post abatement samples.  All work conducted in the enclosure was accomplished using full face respirators with external supplied air, full coverage Tyvek suits, as well as appropriate personal protective gear such as hearing protection, gloves, etc.  

Insulation is sprayed with water prior
to removal to reduce the likelihood
that fibers will be introduced to the
atmosphere.
The removal of the jacket and insulation took approximately a day and a half to remove and safely bag for disposal.  Although the original jacket was in very poor shape, the reason for involving trained museum professionals in the actual remediation was highlighted in the data collected that will be useful as rehabilitation of the locomotive continues.  Hardware such as boiler band brackets, washout plug ferrules, and other assorted hardware was removed, cleaned and saved for reuse.  In addition, various samples of trim treatments, riveting of jacket panels, etc were also saved, and will allow the team to match the original methods of construction as closely as possible.  Illustrating how this benefits the Museum was a discovery made on the inner surface of the jacket located just beneath the hydrostatic lubricator bracket: an uncorroded patch of the original American Iron boiler jacket surface.  Samples such as these are rare because the oxide finish of both Russian and American Iron was extremely prone to corrosion and loss if not kept continuously oiled.  Curator Pappas noted the extremely oil soaked appearance of the jacket and insulation in this area due to frequent overfilling and leakage of the hydrostat over many decades of service, and was particularly mindful of the potential presence of an unadulterated sample.  

Clean boiler!
Following the removal of the material, the arduous process of cleaning all surfaces of the locomotive and containment began.  The next three days were required to assure the successful completion of the job.  The surface of the boiler was rough due to surface corrosion, and provided an ideal surface for asbestos fibers to be trapped and potentially endanger individuals working on the locomotive in the future.  To avoid this possibility, all flaky rust was removed with a chipping hammer and wire brushed while moistened to clean the surface.  More aggressive methods such as needle gunning and wire wheeling are usually not employed as these can raise the concentration of fibers in the containment to unsafe levels, even with full face mask protection.  After this step, all surfaces of the locomotive and containment were vacuumed using a HEPA vaccum cleaner, and all debris double bagged and removed from the containment.  Although this may sound like a relatively simple matter, the work in full protective gear on a hot summer day can be exhausting!

After the insulation was double bagged
and removed, the enclosure room was
cleaned and locked down. An air
sample was collected during a two
hour interval to verify that there was
no airborne fibers prior to removal of
the containment.
Once everything was cleaned, a final wash down with water was conducted over every surface.  The water was then collected below the engine, and pumped through approved water filters to remove any asbestos micro fibers.  All of the secondary inner walls of the containment were sprayed with a fixative called Lockdown, taken down, rolled, and double bagged for removal.  Then all primary surfaces were also sprayed with lockdown and clearance air samples taken.  This last step is critical to assure the safety of anyone in the shop, as once the containment is breached, any contamination will remain.  After the samples were examined by a third party local laboratory, air quality was found to be ideal, with the lowest presence of asbestos recordable!  

Although a great deal of time and effort was expended to conduct this remediation, the money saved, and opportunities for artifact care and documentation were worth the effort.  With this work completed, it is time to finish the boiler work and proceed to the running gear.  Look for more updates soon as Snoqualmie rings with the sounds of heavy boiler work again!  Until then, we hope to see you all in Snoqualmie.  

1 comment:

David said...

Spike, What an undertaking and what a dedicated staff of volunteers! I worked in Safety and Loss Prevention in retailing for years and we had a lot of old stores. Whenever we remodeled and came across asbestos issues, it was indeed an expensive time consuming nightmare. Great job by your team... Take Care, Big Daddy Dave