Exploding Foil Initiator | EFI
When Milliseconds Matter™

EFI – Exploding Foil Initiator.

Slapper Detonator | Fuze | High Voltage Initiator

PacSci EMC / Products / EFI – Exploding Foil Initiator


Exploding Foil Initiator (EFI) Front and Back View

An exploding Foil Initiator (EFI), also known as Slapper Detonator, is used to provide reliable in-line initiation of explosive trains in ordnance systems with a high degree of safety and repeat-ability.

A high voltage pulse applied to the EFI provides the energy and shock needed to detonate insensitive secondary explosives, which further enhances their safety. An electrical stimulus in excess of 500 volts is required to function an EFI, providing enhanced safety in many critical applications, such as rocket motor ignition and warhead initiation. Function times are typically much less than one microsecond. The EFI is an improvement over the similar Exploding Bridge Wire (EBW) detonator with more efficient detonation transfer, lower voltage initiation, increased safety, and the ability to initiate a greater variety of insensitive explosives.

Electronic safe and arm systems are becoming accepted throughout the Space and Defense industry for rocket motor ignition, fuzing, and flight termination applications. These applications require safety sensitive initiation and use what is termed In-Line Initiators (ILI). ILI includes EFIs that are used for warhead initiation applications using detonating outputs and rocket motor ignition applications requiring deflagrating or pyrotechnic outputs. EFI detonators are also used to initiate the destruct mechanisms in flight termination system applications. Application definitions include:

  • ESAD or eSAD – Electronic Safe Arm Device
  • ESAF – Electronic Safe Arm Fuze or Electronic Safe Arm and Fire
  • ISD or eISD – Electronic Ignition System Device
  • FTS – Flight Termination System

Qualified to MIL-DTL-23659 Appendix A for use in PacSci EMC’s eISD, our exploding foil initiators can be found in missiles (from air-to-ground, air-to-air, surface-to-air, surface-to-surface), torpedoes (lightweight and heavyweight), underwater explosive ordnance disposal and precision guided munitions.

Optimal Voltage
1100 Volts nominal

860 Volts at 0.999 reliability at 95% Confidence level

500 Volts, 0.001 probability to fire at 95% SS lower confidence

Operating Temperature
-54°C to +71°C

Ordnance Output

  • Deflagration – Tailored peak output pressure performance in 10cc closed bomb
  • Detonation – 0.010-inch dent depth in steel dent block
  • Thru-Bulkhead – Post-Fire Back Pressure >10,000 PSI

Applicable Specifications
Qualified to:

  • MIL-DTL-23659 Initiators, Electric, General Design For; Appendix A: In-Line Initiator Certification
  • MIL-STD-1751 (Cancelled): Safety and Performance Tests for the Qualification of Explosives
  • STANAG 4170: Principles and Methodology for the Qualification of Explosive Materials for Military Use
  • MIL-STD-1316: Fuze Design, Safety Criteria For
  • MIL-STD-1901: Munition Rocket and Missile Motor Ignition System Design, Safety Criteria For
  • MIL-STD-1911: Hand-Emplaced Ordnance Design, Safety Criteria For
  • RCC-319: Range Commanders Council Flight Terminations Systems Commonality Standard


Exploding Foil Initiator output and input interfaces are adaptable to your system needs.
EFI - Exploding Foil Initiator Technical Envelope



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