Some asbestos-containing valves were simple and only turned on and off the material flow, while other valves were more sophisticated and controlled volume, rates, pressure and even reversed flow directions.
Various valves controlled different materials like:
- Hot water and pressurized steam.
- Crude oil and refined petroleum products.
- Concrete slurries.
- Molten metals and smelted ore.
- Nuclear and radioactive toxins.
- Liquid chemicals
Types of Valves and Valve Accessories
A valve consists of the housing, the gateway and a control handle. These devices are some of the earliest mechanical inventions and have been regulating fluids since the Roman days. Hot water for steam baths and communal pools ran through lead pipes controlled by gate valves.
Once the Industrial Age arrived, inventors created valve systems like:
- Ball valves with circular stops requiring a half turn to open and close.
- Butterfly valves using a semi-circular disc to regulate flows.
- Globe valves which raise and lower in-line plugs.
- Gate valves that slide up and down or back and forth like a fence gate.
- Diaphragm valves with flexible seals pinching off material flow.
At the core of every valve is its seat. This part is the soft material that compresses when closed and expands when relaxed. Other common valve parts are stem packings, gaskets and insulation. From the late 1800s to the early 1980s, many of the millions of valves installed in American ships, factories and buildings contained asbestos.
Asbestos-Containing Materials in Valves
Asbestos-containing materials (ACM) appeared the perfect choice for valve seats, packings, gaskets and insulation. Asbestos was a flexible mineral material with natural fireproofing properties. Not only was asbestos proven to resist fire, but it also controlled temperature and withstand high pressures.
Asbestos valve materials were electrically non-conductive, non-corrosive and chemically inert. Asbestos didn’t react with any material it regulated. Asbestos materials were easy to work with and cost-effective.
There were many reasons to use asbestos valves for these various roles:
- Agriculture and food processing facilities.
- Automotive and machinery manufacturing.
- Chemical producing factories.
- Paper mills and steel smelters.
- Power generating plants.
- Shipbuilding and repair dry-docks.
Valve-making employed two asbestos material classifications. One was chrysotile or white asbestos. This fiber type served lower heat and pressure applications. The other was amphibole asbestos fibers used in high-temperature and extreme pressure valve components. Both asbestos classes were harmful when fibers became airborne and exposed workers to tiny particles. However, amphibole asbestos fiber exposure was far more dangerous.
Asbestos Exposure and Health Risks from ACM Valves
Mesothelioma Justice Network Brief
Health risks from asbestos exposure depended on the number of asbestos fibers, length of exposure and the particular class of asbestos fibers a person inhaled. Different valve designs and installation locations also made a difference in health risks. Anyone working with raw asbestos materials in places like manufacturing plants was at high risk for developing asbestos-related diseases.
That didn’t exclude health risks for others working with valves with ACM products. When workers installed the valves, the fiber exposure occurred. The asbestos was especially toxic when old valve material dried out and started crumbling. Even a small amount of friable asbestos dust could prove deadly. Cramped and poorly-ventilated sites were particularly hazardous.
Mesothelioma and Asbestos Exposure
Mesothelioma is a rare but fatal form of lung cancer. The only cause is from long-term asbestos exposure such as from working around ACM valves. When exposed workers inhaled airborne asbestos, microscopic particles lodged in the lung lining,
Asbestos fibers couldn’t be exhaled, expelled or broken down. They remained permanently stuck in the mesothelium, and this caused a scar tissue build-up. It took anywhere from 10 to 50 years but, eventually, this scar tissue turned into cancer tumors and the fatal disease known as mesothelioma.
Compensation for Mesothelioma Victims
Mesothelioma has no known cure in advanced stages. The only thing to do is to seek compensation. That includes payment for personal injury, lost wages and medical costs from negligent ACM suppliers. Families can represent members with mesothelioma as well as file lawsuits in wrongful death cases.