One of my favorite hazardous materials to work with is Chlorine (Cl2). And yes I know and no I have not been taking my meds! “Like” is probably a poor choice of words to us – Respect is probably more fitting in describing my relationship with Cl2. I have been working with this hazardous material for well over 27 years and have gotten to know it well, thus my utmost respect for it. Many of my anhydrous ammonia clients think I am crazy with the level of safety I expect with NH3, well they “ain’t seen nothing” as my level of safety expectations for Cl2 far exceed that of NH3. Cl2 is just that more hazardous than NH3, even though NH3 has an expansion ratio almost twice that of Cl2; Cl2 is just more hazardous because of its toxicity. Now an expansion ratio of 460:1 is nothing to sneeze at; along with an IDLH of 10.0 ppm and a TLV of 1.0 ppm makes Cl an a_skicker! Take, for example, a single 150 pound Cl2 cylinder…
can cause a 100 sq ft room (with an 8′ ceiling) to go to ZERO % Oxygen and 100% Cl2 gas and it would not take long to do it!
That same 150-lb cylinder can cause a professional football stadium to reach 1 ppm (the 8-hr TLV)!
One pound (or about 11 fluid ounces) of liquid chlorine yields 5.4 cubic feet of 100% chlorine gas (1,000,000 ppm) @ 68F and 14.7 atmospheric pressure
5.38 cubic ft per Pound
11.73 pounds per Gallon
63.10 cubic ft per Gallon
110-pound cylinder = 538 cubic feet of Cl2 gas
150-pound cylinder = 810 cubic feet of Cl2 gas
1-ton container = 10,760 cubic feet of Cl2 gas
So expansion ratio and very low-level exposure limits combine to make Cl2 one of the top HAZMATs we deal with.