Discuss Exact Safety Requirements with Your Safety Consultant
Polyurethanes are produced by reacting diisocynates with polyols and other chemicals. MDI is one type of diisocyanate used in the manufacture of polyurethanes. MDI or polymeric MDI (pMDI) is one component used in the application of polyurethane or polyuria coatings. Special handling and care is needed when spraying these lining products. When using a polyurethane system, the MDI is usually the A-side or the iso-side of the system. The polyol (also called resin) is usually the B-side of the system.
Contact with excessive amounts of polymeric MDI can be harmful to your health. When MDI is sprayed, you may be overexposed by breathing high airborne concentrations of MDI, getting MDI on your skin or in your eyes, and swallowing MDI. If MDI is inhaled, it can cause irritation to the note and lungs. If inhaled over a period of time, a person may feel tightness in the chest and have difficulty breathing. Continued overexposure may cause the body to become sensitized to MDI, which means even very low levels of MDI can cause serious health effects, including asthma attacks. Immediate medical attention is needed if this occurs.
Wear personal protective equipment to avoid over exposure from MDI. When cleaning application equipment, it is recommended that such personal protective equipment (PPE) as safety glasses or splash goggles, MDI-resistant chemical gloves, long-sleeve coveralls and safety boots be worn. Additional protection is needed when spraying. Personal protective equipment, such as splash goggles, MDI-resistant long-sleeve coveralls or full body suits with a hood, and MDI-resistant fitted boots and booties, will help protect from exposure. Respiratory protection, in the form of an approved supplied air respirator (as outlined in most company's Respiratory Protection Program) is also recommended.
Engineering Controls & Ventilation
To further minimize exposure to MDI, appropriate ventilation, combined with a properly designed spray enclosure, is needed. The use of a ventilated enclosure helps to contain spray mists and vapors that develop during the application process. Further, exhaust filters and stacks help to capture the spray mists, which reduce the potential for exposure to those outside the building. It is recommended that a preventative maintenance program for the ventilation system be established to ensure that all of the components of the system (filters, airflow, etc.) are maintained properly. A material should not be sprayed until the ventilation system is operating properly and the appropriate amount of personal protective equipment is worn.