Assuming I am reading this right:
Table 9.1.1(a) is titled "Maximum Quantities of Flammable and Combustible Liquids in Laboratory Units Outside of Inside Liquid Storage Areas (Metric)" and the 150 liter maximum in use and storage of Class 1, II and IIIA is 150 liters per 9.3 m2 of laboratory unit, yes. Those are "high fire hazard class" liquids. That's also presented in English units in Table 9.1.1.(b) for the metrically impaired.
However, the footnotes to the table are very important - Footnote c states "The quantities per 9.3 m2 do not imply the quantities must be within that 9.3 m2 area; the quantities per 9.3 m2 are for calculation purposes to determine the total quantity allowed per laboratory work area and the total amount overall in the laboratory unit"
If you look carefully, the last column of the table lists the maximum quantity per laboratory unit and that is 6,060 liters. The other footnotes reduce these quantities between 25 and 50 percent depending what floor of the building the laboratories are in.
So, to be clear, what NFPA 45 is saying is that you shouldn't have a lot of highly flammable/combustible liquids in a small lab. 9.3 m2 is 100 square feet. 150 liters is 37.5 4-liter bottles. I think we can all agree that amount is too much for a small room that is not provisioned as a flammable chemical storage area. But you can put that or a lot more into any larger lab space.
Let's work an example. If your lab is 20 ft x 20 ft = 400 sf (37 m2) and it has sixty 4-liter bottles (240 liters), the density of Class A flammable in the room is (240 liters)/(37 m2) = 6.5 L/m2. Which is well below the maximum density of 150 L per 9.3 m2 which works out to (150 L)/(9.3 m2) = 16 liters per m2. Rather a poor choice by NFPA in crafting the table - most folks are going to calculate liters per m2 or square foot, not per 9.3 m2 and 100 sf.
Or your specific case, a 60 m2 laboratory can have the lesser of (60 m2)(16 L/m2) = 960 liters or the maximum allowable amount of 6,060 liters. So 960 liters maximum which works out to 240 4-liter bottles. I don't think any one runs even close to that density even in a lab outfitted with a lot of HPLC's etc. Of course, consult the footnotes to the table, because depending on the floor, that could be half the amounts I just listed.
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Ralph's recent post has reminded me about a question I wanted to ask about flammables.
We have a very old (2004) standard:
AS/NZS 2243.10:2004 : Safety in laboratories - Storage of chemicals
That OHS central use as gospel. It does not differentiate disciplines but states 'definitively' that maximum load of solvents is 250L within a 10m radius...even if in DG cabinets and 10L total in the open per lab.
And 'empties' (winchesters, etc) are counted as full while they are still in the lab!
I have tried to search and the best I get is an NFPA (US) 2015 document that if I am reading correctly states 150L / 9.3 M2 without the distance limit. Don't have the whole thing so I may be missing something.
Our labs are around 60M2, loaded with DG cabinets, thermal detectors, fire extinguishers (with training), sprinklers, all graduate chemistry students / post docs, etc.
As you can probably appreciate these limits are close to impossible in a high powered synthetic chemistry lab.
Or has someone found a way?
Comments, suggestions greatly appreciated.
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