Is it safe? A study into the work conditions on the platform during a large scale PennguardTM installation.
It is well accepted among owners and construction companies that health and safety are a prime concern for all parties on a chimney construction project.
Because of this, it is also necessary to understand the effects of installing large quantities of PennguardTM lining materials in chimneys and chimney flues. In 2014, Hadek commissioned the AMD (“occupational medical services”) division of TÜV Rheinland to perform measurements on the Kusile project, at a time when PennguardTM lining installations were ongoing in three flues.
In November 2014, two experts from TÜV Rheinland visited the Kusile site to perform a safety audit over a period of several days. As part of the safety audit, the experts carried out separate measurements for hydrocarbons, carbon monoxide, isocyanates and fine dust.
Hydrocarbons
PennguardTM Adhesive Membrane uses a specific asphalt based technology and when installers use large quantities of this material for the back and side joints of the PennguardTM lining system, this can be clearly smelled on the platform.
TÜV Rheinland’s measurements monitored for a range of hydrocarbons that are emitted into the air during a PennguardTM lining installation, including toluol, o-xylol, cyclohexanol, trimethyl benzol, and others. It was found that, for each substance, the concentrations on the work platform were well below the current workplace limit values in both Germany and South Africa.
Carbon monoxide
The current workplace limit value for carbon monoxide is 35 mg/m³, or 30 ppm. The maximum value measured on the platform (4.8 ppm) was well below this level.
Isocyanates
PennguardTM Adhesive Membrane uses a specific, urethane-based polymerisation technology and isocyanates are a category of potentially harmful chemicals that are used as part of that technology.
TÜV Rheinland used special measuring equipment and a proprietary analysis method to monitor for various, regulated forms of isocyanates on the work platform. It was found that for each these types of isocyanate, the measured value was well below the current workplace limit.
Fine dust
When personnel handle cartons of PennguardTM Block, fine glass dust can be spread over the workplace, especially when unpacking cartons to stack PennguardTM Blocks for the installers around the platform. As part of their investigations, TÜV Rheinland monitored fine dust concentrations on all three active work platforms.
On two of the three work platforms, the measured dust concentrations remained well below the German workplace limit value of 3.0 mg/m³, and even below the revised workplace limit value of 1.25 mg/m³ that must be achieved by end of 2018. On the third platform however, total dust and fine dust concentrations were measured to be well above the current workplace limit value.
TÜV Rheinland’s measurements indicate that, although fine dust concentrations surrounding a large scale PennguardTM lining installation can be very low, elevated fine dust concentrations can sometimes occur.
TÜV Rheinland recommend, that all personnel should use “FFP-2” particulate filtering masks. These masks are relatively inexpensive, as well as readily available.
The Mixing Station
On nearly all large PennguardTM lining projects, the PennguardTM Adhesive Membrane is now mixed using Hadek’s automated mixing machines. TÜV Rheinland payed special attention to the safety in the Mixing Area, where several of these machines were working nearly all of the time.
The work environment in the Mixing Area was found to be safe, with all measurements for hydrocarbons, carbon monoxide, isocyanates and fine dust well within the current workplace limit values. The Mixing Zone is a noisy place though, with a measured sound pressure up to 96 dB. Earplugs must be used here.
Important points:
- TÜV Rheinland did not perform a safety audit of the grit blasting and primer application works.
- This report describes the situation found at the Eskom Kusile project. Each customer must consider the circumstances of his own project to achieve a safe work environment.
- Interested customers may request to receive a copy of TÜV Rheinland’s full report.
A new primer for steel substrates: PennguardTM HP Epoxy Primer
Before installing the PennguardTM lining system onto a steel chimney or a steel chimney flue, the surface is grit blasted to a “near white” (SA 2 1/2) cleanliness, made dust-free and coated with a primer. PennguardTM Block Primer has traditionally been used for this, and it offered compatibility with the PennguardTM lining itself as well as excellent application properties even for crews with limited experience in spray application methods.
In recent years, it has become customary for chimney builders to perform grit blasting and primer application in a location well removed from the chimney itself, avoiding any grit blasting and spray painting activities on their core construction site. For projects of the size of Medupi and Kusile, this means that large numbers of steel flue sections are lined up at a remote location, waiting to be moved to the chimney at some time.
While it is always recommended to keep grit blasted and primer coated steel flue sections dry and away from direct sunlight, this is sometimes hard to achieve and by the time the steel flue sections reach the chimney, localised corrosion may have occurred that results in expensive and time-consuming repairs.
The PennguardTM lining is system is now offered with the option of a new, thicker, more durable primer, the PennguardTM HP Epoxy Primer. Unlike the dark orange PennguardTM Block Primer, the new product is white. PennguardTM HP Epoxy Primer is typically applied at a dry film thickness of 37-62 µm. At this thickness, the material cost is virtually the same as that of PennguardTM Block Primer. The application of the new primer is however more labor intensive and it requires more skill from the applicator.
PennguardTM HP Epoxy Primer was first used on a large scale at the Kusile project and it was found to work very well.
