As with any industrial facility, there are certain safety risks present in simple cycle gas plants that must be monitored and mitigated when there is an issue.
While there are numerous hazards that employees in your gas power plant have to navigate on a regular basis, there are two that are regulated and must be compliant with safety standards: exhaust system heat levels and noise exposure.
Exhaust System Temperature Standards in Simple Cycle Plants
Gas turbine exhaust systems are designed to safely direct exhaust to atmosphere. During the power generation process, the exhaust can be in excess of 1000°F. That’s why a safe operating temperature must be maintained on the outside casing plate, where plant employees may have contact. The target temperature is typically 140°F, and that is achieved with the use of an internal liner system within the ductwork.
The liner system is crucial to the safety of the simple cycle gas power plant. Unlike combined cycle gas plants, the simple cycle plant doesn’t have a heat recovery steam generator (HRSG) at the exhaust. As a result, the stack and the whole exhaust duct has to have an effective liner system in place. The floating liner system is typically comprised of:
- Solid sheet of grade 409 stainless steel internal liner
- Insulation layer with the thickness based on the thermal performance requirement
- External casing plate
The liner system is designed to keep the average temperature of the casing pate at 140°F for the safety of employees.
Metal Ejecting from the Stack
When insulation is evacuated from a stack it can be due to initial welds breaking. This leads to silencer baffle insulation or liner insulation being pulled out by the exhaust flow. The insulation in the silencer baffles is a lot of their weight. Without it the baffles deteriorate faster and chunks of perforated sheet and metal framing can come loose and even ejected from the stack. Clearly this is a significant safety issue.
In addition to the safety problem, this can also lead to back pressure issues. When this happens the control room can see it as it negatively impacts turbine performance. This can lead to emergency outage work to patch up the system in order to get it to an outage where more repairs, replacements and upgrades can be considered.
Noise Exposure Standards for Simple Cycle Gas Plants
In power plant settings, hearing loss is one of the most common health conditions employees suffer from. Exposure related hearing impairments are associated with both the duration and the level of the noise a worker experiences. As a result, the Occupational Safety and Health Administration (OSHA), an agency of the United States Department of Labor, implemented safety standards designed to protect the hearing of employees in industrial jobs.
The standards that are in place apply to individuals who are exposed to a time weighted noise level of 85 dBA or higher, on average, over an eight-hour shift. Employers are required to measure noise levels, provide employees with free annual hearing exams, and provide hearing protection and training for all workers exposed to noise levels of 85 dBA or higher.
In addition to the noise exposure that is experienced by workers (near-field exposure), simple cycle gas plants also must be concerned with noise that surrounding communities or neighboring businesses are exposed to (far-field exposure). While there are no federal regulations that determine acceptable far-field noise levels, local jurisdictions have and enforce their own noise exposure regulations. Most jurisdictions designate a specific dBA limit for a specific distance, which may vary based on the zoning (residential, commercial, or industrial) in the affected area. Power plants that don’t abide by the standards can be held legally accountable and that can be very costly.
SVI Dynamics Helps Simple Cycle Gas Plants Maintain Safety Standards
Maintaining acceptable levels of heat and noise is essential for your simple cycle gas plant. At SVI Dynamics, we can help you meet those requirements, keeping your workers safe and your neighbors happy. Our team is available to come to your power plant and provide an inspection to determine if you have any thermal or noise control issues.
SVI Dynamics can mitigate any problems that are identified including equipping appropriate machinery with silencers and installing industrial acoustic noise enclosures when needed. With the proper equipment, noise levels are reduced to a safe level for employees. Additionally, for issues with excessive temperatures in the exhaust system, we can design and install a liner system that meets your temperature goals.
If your plant is like many other simple cycle gas plants, then you are running original exhaust systems that were designed using methods and materials that are more than a decade old. SVI Dynamics can help you take advantage of more modern approaches to increase efficiency and safety.
If you would like to learn more about the services we provide, please contact us with any questions today.