Asbestos tends to be a cringe-worthy word for most, and it’s no different when it comes to pipelines. Asbestos was widely used as an effective means to protect steel pipes from corrosion and the elements. Unfortunately, over time it becomes friable, or easily crumbled, and that’s when it starts to become a hazard. In the past, utilities used two types of asbestos products: asbestos asphaltic (coal tar) wrapped pipe; and asbestos-cement (Transite) pipe.
Utilities are continuing to look for effective ways to properly remove asbestos-based asphalt coatings from underground piping before it becomes friable. But if the pipe has reached the end of its useful life or has friable asbestos, there are several site remediation options to consider before beginning.
- Abandon the pipes in place. When considering the end of life for a pipeline with potential health and environmental impacts, it must be considered that a safer solution may be to leave the pipe undisturbed in the ground.
In this situation, a utility must consider the future state of the pipeline and the environment from which the pipe would be removed. If a pipeline is in stable soil and in an area in which new development is unlikely to disturb it, it may be a good candidate for abandoning in place.
Abandoning in place does not simply allow the pipe owner to walk away. It requires a contractor who is familiar with the requirements of the 49 CFR § 192.727. For example, typical abandonment includes filling the pipe with low-density, flowable concrete known as cellular, or foam, concrete.
- Reuse as a carrier pipe. Though a pipeline may reach its end of life, the pipe could still be utilized with additional equipment to allow the transport of fluids or information.
Reuse of asbestos lines as carrier pipes offers an option to repurpose a pipe’s right-of-way with minimal disturbance to the pipe and the surrounding environment. It will, however, require strategic excavation and unearthing of small pipeline sections. As infrastructure needs change, a utility may encounter a situation in which the flow rate is reduced in a system and a smaller pipe can replace a larger pipe. Larger asbestos pipes can act as a route for several smaller pipes and even traditional data cables and fiber-optic lines.
When recycling a pipe as a casing for other pipes and conduits, the new line(s) can be rigid or flexible pipes, made of metal, thermoplastics, or a combination of the two in a multilayered system. Flexible lines are typically pulled from one end, which can be done for a single pipe or multiple lines within the recycled casing pipe. This can be achieved with minimal abrasion to the casing pipe.
Alternatively, by using pipe spacers and strategic excavation locations, disturbances can be reduced and contact between multiple lines eliminated. Pipe spacers make it possible to combine rigid and flexible lines within the same casing pipe without fear of pipe-to-pipe damage.
- Replacement of pipes. If reusing the pipe is desired but recycling the old pipe as a casing pipe is not possible, then a pipe may be safely removed and replaced.
Replacement of pipes is the costliest option for remediating asbestos pipelines; however, there can be significant advantages gained through the reduced environmental impacts associated with this approach, and the added advantage of safely removing potentially dangerous pipe materials. It is also the only method that can maintain the same flow rate for fluids in the pipeline.
This process requires specialty contractors with certificates and licensing specific to each state. Pipe replacement takes advantage of existing rights-of-way, which are maintained through the removal of debris and unwanted and overgrown vegetation. The removal process requires mitigation to prevent friable asbestos from being liberated during excavation, often with the use of water and hand tools once workers are within a specified distance of the pipe.
- Removal of pipes. If a utility no longer has a use for a pipeline route or there is a possibility for future disturbance to the pipe or surrounding soils, then the only remaining option is the safe removal of the piping.
Total removal of pipes may be employed in combination with abandonment in place, for sections at risk of future disturbance. Pipeline removal requires consideration of safe pipeline excavation, temporary pipeline storage to allow required pipe testing, safe transport, and final disposal at specialty asbestos-accepting landfills.
When followed correctly, proven removal procedures are safe and maybe the most effective option to nearly eliminate future environmental impact liability.
Finding the Solution
It is important to evaluate options for the remediation of asbestos-coated piping that are sustainable and environmentally friendly while also allowing the needed energy and power to flow through the pipeline to the communities it serves. Every remediation project is different and thus the approach must be tailored to meet the specific needs of each site and project type. Working with an experienced remediation strategy partner can make the process smoother.
Complex site remediation is just that: complex. Focused, data-driven remediation solutions that use an integrated approach can deliver cost-effective, predictable results.