Agreed. I have never "activated" the safety in mine but it is a frangible section in a replacable screw-in fitting. I estimate the failure section to be some 3-5 mm in diameter (not exactly clear where it would fail). It would release steam as fast as a stove could form it. I'm not sure it needs to be replacable. I've heard most people who have your aunt's experience never pressure cook again. :)
They speed up cooking around 3:1, but they are at least slightly scary. Pot roast in a hour makes it worthwhile. Many brands available in the US are imported, and marked in liters. A bomb blast would create too much overpressure for the safety and blow the cooker apart regardless of brand. Steam pressure builds slowly based on time to heat the water. It may take 15 minutes to get to nominal cooking pressure, moreless the trip pressure, if it is half full. ________________________________ From: "Hillger,Donald" <don.hill...@colostate.edu> To: U.S. Metric Association <usma@colostate.edu> Sent: Wed, April 17, 2013 9:27:57 AM Subject: [USMA:52682] RE: Bombs Used in Boston Marathon Are Common in South Asia - NYTimes.com Ok, let’s get the record straight here! I’ve used pressure cookers a lot and they have safety values, but they only allow the pressure to release fast enough to avoid normal overheating. An aunt of mine actually had her pressure valve blow and it plastered the ceiling above the stove with the food contents inside. However, a bomb going off is certainly not going to be abated by a pressure relief value! From:owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf Of Martin Vlietstra Sent: Wednesday, 17 April 2013 06:37 To: U.S. Metric Association Subject: [USMA:52681] RE: Bombs Used in Boston Marathon Are Common in South Asia - NYTimes.com Pressure cookers should have safety devices to prevent them from exploding. Although we do not have a pressure cooker at home, I remember that my mother’s pressure cooker had a rubber stopper that would dislodge should the pressure rise too much. On reading the account, it occurred to me that the pressure cooker used in the explosion could have been bought in country that did not demand safety valves on their devices. (I assume that in the US it would be illegal to sell pressure cookers without safety valves). From:owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf Of Nat Hager III Sent: 17 April 2013 12:08 To: U.S. Metric Association Subject: [USMA:52678] Bombs Used in Boston Marathon Are Common in South Asia - NYTimes.com Oh wow. About to get some unwelcome publicity. Nat http://india.blogs.nytimes.com/2013/04/17/what-are-pressure-cooker-bombs-and-why-do-terrorists-use-them/ >Forensic experts described the pressure cookers used in the Boston marathon >blasts as generic, but noted the marking “6L,” indicating six liters. >Pressure >cookers in the United States are most often measured in quarts, not liters.
