May 29, 2018
To help ensure long-term pavement durability on bridge decks coated with the Bridge Preservation™ waterproofing system, it is recommended that adequate membrane-level drainage be provided to ensure water is quickly removed from the bridge deck. Poor drainage results in pavement that is saturated with water, leading to accelerated deterioration of the pavement including potholes, cracking, stripping, and debonding. These issues are further exacerbated because bridge decks experience more freeze-thaw cycles than the adjacent roadways on grade.
In addition to membrane-level drainage, there are additional considerations when designing a waterproofing-asphalt assembly, including, but not limited to, tack coat selection, tack coat application rates, asphalt thickness, and adequate compaction.
May 17, 2018
As of August 8, 2013 The Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for methylene diphenyl isocyanate (MDI) is 20 ppb as a Ceiling Limit. The recommended Threshold Limit Value-Time Weighted Average (TLV-TWA) established by the American Conference of Governmental Industrial Hygienists (ACGIH) for MDI is 5 ppb.
Three separate air monitoring tests of polyurea and polyurethane spray applied coating systems containing MDI were evaluated.
All tests found the TLV-TWA for MDI exposure to be less than ACGIH limit of 5 ppb or the OSHA PEL of 20 ppb. The following are best practices when spraying aromatic polyurea;
This memorandum does not purport to address all the health concerns regarding the application of spray applied coatings, and should only be used for evaluation and screening purposes. In order to properly assess actual employee exposures IAW OSHA requirements, please follow all local, state, and federal regulations.
October 17, 2018
Please consider placing your order before cold weather hits and transport becomes a serious concern. For smaller orders, also keep in mind that Fed Ex and UPS do not have heated trucks, meaning your material could face wide temperature fluctuations during its trip. This bulletin is to inform customers about the “best practices” for shipping, handling, storing, and installing Bridge Preservation™ systems during cold weather/winter conditions.
While Bridge Preservation makes no guarantee that following these guidelines will result in a more usable product, it is our estimation that these suggestions should be touchstones for best practices during the parts of the year with cold weather.
Shipping material during the cold winter months will reduce the internal temperature of the material and therefore will need to be warmed to recommended temperature levels prior to installation/application.
Temperature Conditions: minimum of 60°F to 95°F, (18°C to 35°C).
Temperature Conditions: It is recommended the material temperature be a minimum of 70 Degrees F, or higher. It is also recommended that a Laser Temperature Gun be available for accurate temperature readings before and during installations.
For cold (on-site) environments it is important to keep material in heat boxes or heated rooms. Installing material where ambient conditions and/or floor temperatures are below 60 degrees, material should be stored at 70 degrees F or above. The utilization of tank heaters/blankets and hose line heat tape is useful in maintaining the proper material temperature.
In cooler temperatures material viscosity is increased which puts more strain on proportioning equipment. Monitoring and maintaining recommended temperatures is a simple way to reduce the risk of processing issues that lead to additional costs.
Of course, you can always use supplemental heat to warm the area or asset you’re trying to coat. If you do this, be very, very careful if you’re working in a confined space and pay attention to the substrate temperature, not the air temperature. That is, if you’re coating a fire hydrant, and you build a tent around the hydrant, don’t check the air temperature, check the temperature of the steel.