Explosibility testing

Deflagration Arrester Testing For end-of-line and tank vent flame arresters, approval agencies may require manufacturers to provide users with data for flow capacity at operating pressures, proof of success during an endurance burn or continuous flame test, evidence of flashback test results (for end-of-hne arresters) or explosion test results (for in-line or tank vent arrester applications), hydrauhc pressure test results, and results of a corrosion test. 

FIG. 26-30 Siipp ression of explosions, Pressures in an ethylene explosion and a sodium bicarbonate suppressed ethylene explosion, Tests conducted by Fike Corp, in a 1-m vessel. Ethylene concentration = 1,2 times stoichiometric concentration for combustion, (dp/dt)e = 169 bar/s (2451 psi/s), = reduced explosion pressure = 0,4 bar gauge (5,8 psig), (F/om Chatrathi, Explosion Testing, Safety and Technology News, vol. 3, issue 1, Pike Cotp., 1.98.9, hy permission. )... 

Explosion Testing, Including Dust Explosibility and Ignitability... 

Explosion testing should be performed to establish safe operating limits. Dust explosibility and ignitability are measurements of the potential for a combustible material, in dust form, to explode or ignite. Any combustible material has the potential to cause a dust explosion if dispersed in air as a dust and ignited. Further details on explosibility testing can be found in Palmer (1973), Bartknecht (1989) and Eckhoff (1997). 

If it is assumed that explosible dust will be present above the MEC, and equipment design data are not required, explosibility testing forP g, and Kg usually has no direct application. However, minimum ignition energy (MIE) testing should be considered to help determine the likelihood of ignition. Since MIE is extremely sensitive to particle size it is especially important to test a sample that is sufficiently fine to represent the worst credible case. 

A manufacturer of ethylene oxide received some old returned cylinders in which the ethylene oxide had partly polymerized, sealing the valves. They were taken to an explosives testing site and blov/n up [20]. 

FIgura 4.4. Obstacle array used in large-scale propane explosion tests by Zeeuwen et al. (1983). 

Schwab, R. F., Interpretation of Dust Explosion Test Data, Loss Prevention, Vol. 2, Amer. Inst. Chem. Engr., 1968, p, 37. 

Non-Permissible (Amer) or Non-Permitted Brit) Explosives. See under Commercial or Industrial Explosives in Vol 3, C435-R to C437-R, and Coal Mining Explosives, Testing for Permissibility in Vol 3, C368-R ff... 

Nearly all recognized detonating explosives have oxygen balances between -100 and h-40. Any substance with an oxygen balance higher than -200 should be treated as potentially dangerous and explosibility testing for these compounds should be carried out. 

Further properties which a detonating fuse should have are the ability to initiate blasting explosives (tested with suitable relatively insensitive mixtures usually of TNT and ammonium nitrate) resistance to low temperatures without cracking on flexing and to hot storage without desensitisation and toughness to prevent damage from stones, etc. The fuse must always be waterproof and must often withstand diesel oil, which can separate from ANFO. 

Nitromethane may act as a mild oxidant, and should not be heated with hydrocarbons or readily oxidisable materials under confinement [1]. Explosions may occur during cooling of such materials heated to high temperatures and pressures [2], Mixtures of nitromethane and solvents which are to be heated above the b.p. of nitromethane should first be subjected to small-scale explosive tests [2],... 

An 850 kg batch of a slightly doped form of azodicarbonamide exploded violently, with a TNT equivalence of 3.3 kg, 5 minutes after sampling at the end of drying. The probable initial temperature was 65°C, the lowest self accelerating decomposition temperature 90°C, and such decomposition is not explosive. Full explosibility tests, including detonability, had shown no hazard. Further study demonstrated that slightly contained azodicarboxamide, thermally initiated at the bottom of a column or conical vessel could explode even at the 5 kg scale. The above TNT equivalence corresponds to decomposition of 4% of the available charge. The cause of the presumptive hot spot is unknown. 

This material, and homologues, are being recommended as oxidants, they are prepared in situ and very dilute. Thus far, the material has shown itself surprisingly stable during isolation and pyrolysis (decomposes slowly at ambient temperatures and quietly on heating) and even explosivity testing [1], However several... 

The peroxyester explodes with great violence when rapidly heated to a critical temperature. Previous standard explosivity tests had not shown this behaviour. The presence of benzene (or preferably a less toxic solvent) as diluent prevents the explosive decomposition, but if the solvent evaporates, the residue is dangerous [1], The pure ester is also shock-sensitive and detonable, but the commercial 75% solutions are not [2]. However, a 75% benzene solution has been exploded with a detonator, though not by mechanical shock [3],... 

Explosibility of individual substances Detonation Deflagration Chemical structure Tube test Card gap Dropweight Oxygen balance High rate test Explosibility tests... 

Specific explosibility tests are discussed in this section. It is emphasized that detonation tests in particular and a number of deflagration tests are of the type that must be run by experts in specialized facilities. 

More complicated explosibility tests need expert advice and specialized facilities. If your calculations or testing demonstrate potentially explo-... 

Differential scanning calorimetry (DSC) and dust explosion tests are usually conducted before a new chemical goes into the pilot-plant phase. 

Finding (Blue Grass) EFKE-2. Energetics from fuzes and burster assemblies will probably not be destroyed in COINS, and downstream equipment must be able to handle this situation. Explosivity tests conducted by the technology provider showed that these materials decompose in the TRBP environment rather than explode or detonate and that the TRBPs will accommodate the decomposition of these explosive materials. 

Following the Birmingham Six case, the Griess test has become somewhat discredited by the forensic community. It should be emphasized, however, that when properly used, it is an excellent tool which can serve as a basis for an efficient field test. An explosive detection kit (ETK (explosive testing kit)), partly based on the Griess test, was successfully used in Israel in several terror and non-terror investigations [49] (see below). 

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