Spark sensitivity

Spark sensitivity values for a series of pyrotechnic compositions are given in Table 6.1. It can be seen that these values tend to be considerably greater than 0.10 J, unless a line metal powder (such as aluminum) is used. Keep in mind that spark sensitivities can vary greatly for a given oxidizer-fuel mixture, with the particle size and surface oxidation state of the fuel often playing a very significant role. A manufacturer cannot rely on spark sensitivity results other than those obtained on compositions produced by his company. 

Electrical Spark Sensitivities of Various Pyrotechnic Compositions 

Military white flare mixture Sodium nitrate 49 

Rash powder (fine powder) Dark pyro aluminum 

Potassium perchlorate (fine) Potassium perchlorate (coarse) 

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Table 9 lists the chief performance characteristics of the most important delay compns. In general, the bum time is controlled within the stated limits by adjustment of the fuel fraction. Other variables are the particle size of the fuel and the presence of additives such as Pb chromate, silica and Viton. Many perchlorate containing mixts are friction and spark sensitive,... 

In devices which can tolerate moderate ignition delay, further development of non-primary initiators (Refs 31, 77, 97 112) will extend the storability, the manufacturing safety, the electromagnetic Held and spark sensitivity and the high temp compatibility of pyrotechnic devices... 

The neat material is about three times as shock-sensitive as glyceryl nitrate, and should not be handled undiluted [1]. It exploded during vacuum distillation at 3.3 mbar from a bath at 140°C. Impact- and spark-sensitivities were determined, and autoignition occurred after 30 s at 107°C [2], An explosion occurred during distillation at a pot temperature of 80°C. Full handling precautions are detailed. Dilution of neat material with solvent eliminates shock-sensitivity [3],... 

The endothermic nitride is susceptible to explosive decomposition on friction, shock or heating above 100°C [1], Explosion is violent if initiated by a detonator [2], Sensitivity toward heat and shock increases with purity. Preparative precautions have been detailed [3], and further improvements in safety procedures and handling described [4], An improved plasma pyrolysis procedure to produce poly (sulfur nitride) films has been described [5], Light crushing of a small sample of impure material (m.p. below 160°C, supposedly of relatively low sensitivity) prior to purification by sublimation led to a violent explosion [6] and a restatement of the need [4] for adequate precautions. Explosive sensitivity tests have shown it to be more sensitive to impact and friction than is lead azide, used in detonators. Spark-sensitivity is, however, relatively low [7],... 

CAUTION This mixture is extremely spark sensitive and must be handled accordingly. 

A good source of ready-made thermate is the U.S. military AN M-14 Incendiary Grenade. To remove the thermate, first pry out the fuse assembly with crimpers or other nonsparking implement. See Figure 61. The reddish-brown caked substance on top of the contents of the grenade is a first fire mixture and it is spark sensitive. This should be broken up and the grayish powder beneath, which is the thermate, can be poured out. 

Reddy, G. O. et al Thermochim. Acta, 1983, 66, 231-244 Of the four salts with Hg2+, Pb2+, Ba2+ and 2Na+, the thermal sensitivity and impact-, friction- and static spark-sensitivities decreased in that order, as expected. These and other entries are ... 

CA 60, 3944(1964) [Friction and spark sensitivity of igniter compns contg Zr pdr and oxidizers (such as Fe oxides), is decreased in controlled manner by varying the thickness of a coating of an organo-polysiloxane (such as dimethyl- or methyl-phenyl-polysiloxane, used in quantities 0.5 to 5.0% by wt) on the Zr particles. 

Electric Spark Sensitivity to. MF is capable of being ignited by a spark from a person charged to less than 5000 volts, a condition that is possible in plant operations. Brown et al (Ref 27) give for Sensitivity to Electrostatic Discharge 0.025 joules (Ref 34)... 

Rate of Detonation. See Detonation Race Rifle Bullet Impact Test — not found Sand Test. See under Brisance Sensitivity to Electric Spark or to Electrostatic Discharge. See under Electric Spark Sensitivity to Initiation — not found Sensitivity to Pressure. When pressed at pressures in excess of 25000psi,. MF will... 

The impact, friction and spark sensitivities of pyrotechnic formulations are assessed by the methods given in Chapter 3. The outlines of methods for the determination of burning rate, luminous intensity, IR intensity, and total obscuring power of smoke are given in this section. 

As discussed under explosives and propellants, a number of energetic binders GAP, NHTPB, poly(NiMMO), poly(GlyN), poly(BAMO), poly(AMMO) and BAMO-AMMO copolymers etc. have been reported in the recent past and are at various stages of development and introduction for bulk production of explosives and propellants for various applications. These polymeric binders are reasonably stable and are of established compatibility with a wide range of ingredients used for explosive and propellant formulations. The data on their explosive properties impact, friction and electric spark sensitivities, indicate that it is safe to handle these materials. However, there appears to be no report in the open literature on... 

P.W.J Moore, J.F.Sumner R.M.H. Wyatt, The Electrostatic Spark Sensitiveness of Initiators Part I—Introducr tian and Study of Spark Characteristics , ERDE(Explosives Research. and Development Establishment) Report4/T/56, Waltham Abbey, Essex, England (Jan 1956)... 

The Electrostatic Spark Sensitivity of Bulk Explosives and Metal/Oxidant Mixtures NA.VORD Rept 6632 (June 1959)... 

Spark Sensitiveness of Initiators, Part IV—Initiation of Explosion by Spark Radiation , ERDE Rept 9/R/59 (August 1959) 23) R.M.H. Wyatt, Ibid,... 

The reader is referred to Ref 1 for a voluminous compilation of detonation properties (detonation velocity and diameter effect, cylinder test performance, plate dent test and detonation failure thickness), shock initiation properties (wedge test data and small and large - scale gap tests), and sensitivity tests (skid test, large-scale drop test or spigot test and spark sensitivity) relevant to LASL research expls Refs 1) T.R. Gibbs A. Popolato, LASL Explosive Property Data , Univ of California Press, Berkeley (1980) 2) B.M. Dobratz,... 

Spark Sensitivity of Explosives. See under Electrostatic Discharges and Sensitivity of Explosives to Initiation by Them in Vol 5, E38-Lto E55-L... 

TNT, like RDX and Composition B, is not classified as dangerous with respect to hazard from electric sparks. Sensitivity to electrostatic discharge of TNT (thru 100 mesh) is 0,06 Joules (unconfined) and 4.4 Joules (confined) TNT can be detonated by electric discharge (Ref 108)... 

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