CertiGuide to A+ (A+ 4 Real)  9  Chapter 12: Material Safety: a Personal and Technical Report on Hazardous Material Handling       9  Reading and Understanding MSDSs            9  Section Four - Fire/Explosion Data

Flash Point 1 Section Five - Reactivity Data

MSDSs will almost include some general fire information about what is likely to occur when using the product. Examples in this MSDS are common sources of ignition, container explosion because of excessive heat and that this product produces flammable vapors are heavier then air. The last few sentences of the general fire information in Tcat’s Unreal Kleen bear repeating here. These can be real “gotchas“when using products that off-gas heavier-than-air flammable vapors.

… which may accumulate in, low areas and/or spread along ground away from usage site. Possible ignition of accumulated vapor in low areas may occur long after the use of this product. Ignition of the vapor spread away from the usage site may flash back to the usage site.

The final pieces of information in this section are hazard ratings of the National Paint & Coatings Association (NPCA)¹⁵⁵ Hazardous Materials Information System¹⁵⁶ (HMIS) and the National Fire Protection Association¹⁵⁷ (NFPA) 704. Both of these ratings systems are more in the domain of labeling, but are quite often included in MSDSs. Would anyone be surprised if I said that some MSDSs will list both of these ratings, some will list one but not other and other won’t list either or that you may find these ratings in just about any place in a MSDS?

Each of these systems utilize hazard four categories, values that range from 0 to 4 (except in the forth „white“category) and each category is represented by a different color representing one of the hazard categories. A low number such as a 0 or a 1 indicates a slight or low level of hazard while a high number (3 or 4) equals a high or great hazard level. Blue identifies the health hazard level, red identifies flammability and yellow identifies the reactivity hazard. The last category uses the color white and depending on what system is used, this substance represents a specific hazard or required personal protection. In most MSDSs, this fourth „white“ category is omitted and as most MSDSs are printed in black and white, the practice of spelling out the hazard category (or just its initial) is commonly used.

Although both systems have many similarities, they are different systems. The NPFA 704 is geared to emergency responders, particularly the fire department, while the HMIS system is geared toward communicating chemical hazards in the workplace. The NCPA maintains that the two systems utilize different value criterion of each category that could result in a different hazard value being assigned the same substances. However, in real life, I have seen very little to support this and as such, believe that the ratings are similar enough that inter-use of the two should not create any significant problems.

The NFPA uses a square on end (diamond shaped) divided into four quadrants while the HMIS labeling constitutes of colored bars (usually vertical) for their labeling. Because of a universal recognition that square on end indicates hazard, the HMIS system is often used on square on end style of labeling. However, both associations frown on such hybrids of the two systems (see Figure 413).

Both systems have been recently revised. In 1996, the NFPA changed the reactivity category to that of instability. In the spring of 2002, the NCPA release their HMIS III (revision 3) that changed the reactivity category to a physical hazard category and changed the color from yellow to orange. Additionally, the flammability criteria have changed to be more in line with OSHA definitions. As of yet, I have not witness much evidence that MSDSs readily has adopted these revisions. The three main categories of health, flammability and reactivity are still dominant.

Flash Point 1 Section Five - Reactivity Data