IL-STD-464D was released on December 24, 2020. This revision is in keeping with the routine five-year revision cycle applicable to many such standards, and MIL-STD-464 must keep in sync with MIL-HDBK-235, from which the electromagnetic field intensity tables are drawn. In this case, the routine five-year cycle took ten years to complete.
MIL-STD-464 is the U.S. Department of Defense (DoD) top-level E3 requirement set for the procurement of complete or modified systems. In this context, systems means an integrated platform of one type or another, such as a ground or air vehicle, a ship or submarine, a spacecraft, or launch vehicle. Note that some systems can be parts of other systems, such as an F-18 fighter aircraft that operates from an aircraft carrier.
The original release of MIL-STD-464 was in 1997. MIL-STD-464A (2002) and MIL-STD-464C (2010) provided minor, evolutionary changes to the original release.1
Compared to MIL-STD-464C, the changes in MIL-STD-464D are very minor. This article serves as a laundry list of the substantive changes, including the EME tables, and indications of what values changed in the EME tables, so that the reader may see at a glance where the changes are, rather than checking each table row-by-row and cell-by-cell.
The purpose of this article is to inform and save the reader the time the author spent combing through MIL-STD-464D vs. MIL-STD-464C (referenced as D and C throughout the rest of this article). Entertaining the reader was not a practical goal.
3.1 All-up-round (AUR)
3.2 Bare devices
3.3 Below deck
Extended to include the pressure hull of a submarine.
3.7 Energetics
3.8 Flight deck
3.12 Helicopter-borne electrostatic discharge (HESD)
3.13 High power microwave (HPM)
Deletes the frequency range.
3.18 Maximum no-fire stimulus
3.22 Ordnance (fewer words than C)
3.23 Personnel-borne electrostatic discharge (PESD)
3.27 Spectrum-dependent systems
Adds this statement at the end:
3.34 Vertical replenishment (VERTREP)
3.35 Weather deck
5.1 Margins (MIL-STD-464D)2
Compare this with the text in C, as follows:
“Margins shall be provided based on system operational performance requirements, tolerances in system hardware, and uncertainties involved in verification of system-level design requirements. Safety critical and mission critical system functions shall have a margin of at least 6 dB. EIDs shall have a margin of at least 16.5 dB of maximum no-fire stimulus (MNFS) for safety assurances and 6 dB of MNFS for other applications. Compliance shall be verified by test, analysis, or a combination thereof. Instrumentation installed in system components during testing for margins shall capture the maximum system response and shall not adversely affect the normal response characteristics of the component. When environment simulations below specified levels are used, instrumentation responses may be extrapolated to the full environment for components with linear responses (such as hot bridgewire EIDs).
When the response is below instrumentation sensitivity, the instrumentation sensitivity shall be used as the basis for extrapolation. For components with non-linear responses (such as semiconductor bridge EIDs), no extrapolation is permitted.”
5.2 Intra-system electromagnetic compatibility (EMC)
5.2.2 Shipboard internal electromagnetic environment (EME)
The very last sentence in C section 5.2.2.b after the listing of the individual device and total EIRP is not found in D. This sentence in C that is not in D reads:
Also, whereas verification in C is by test in all cases, in D, for submarines an analysis consisting of a summation of all individual device EIRP into total radiated power (TRP) is allowed.
(See Tables I – VI, pages 80, 81, and 82)
5.5 Lightning
Has some expanded wording about near strikes and slightly different wording describing Figure 2 and Table VII.
5.7 Subsystems and equipment electromagnetic interference (EMI)
Now includes new wording (in non-italicized text in the excerpt that follows):
‡ The EME levels in the table apply to shipboard operations in the main beam of systems in the 2700 to 3600 MHz frequency range on surface combatants. For all other operations, the unrestricted peak EME level is 12667 V/m and the unrestricted average level is 1533 V/m.
TABLE II: Maximum external EME for ship operations in the main beam of transmitters vs. -464C TABLE 2. External EME for shipboard operations in the main beam of transmitters
5.7.1 Portable electronic devices and carry-on equipment requirements
Newly added in D, as follows:
- Safety Critical: All platform emissions and susceptibility requirements (such as those defined in MIL-STD-461) that are defined for safety critical equipment.
- Non-Safety Critical: All platform emissions requirements (such as those defined in MIL-STD-461).
“If any part of the portable electronic device/carry-on equipment contains radio frequency transmission capability, then transmitter emissions characteristics shall be measured (such as in MIL-STD-461 Test Method CE106), in addition to the applicable requirements stated above. An aircraft EMC evaluation per 5.2 shall also be required to demonstrate platform compatibility of the portable electronic devices/carry-on equipment which have radio frequency transmitting capability.
“If any part of the portable electronic device/carry-on equipment contains ordnance or is integrated into an ordnance system, then the HERO requirements stated within this standard shall also be met. Compliance shall be verified by test per the applicable requirements.”
NOTE: *denotes no emitters in that frequency range.
TABLE III: Maximum external EME for space and launch vehicle systems vs. -464C TABLE 3. External EME for space and launch vehicle systems
5.7.3 Shipboard DC magnetic field environment. (5.7.2 in C)
In the C revision, this requirement could only be verified by test. In the D revision, the ubiquitous phrase, “Compliance shall be verified by test, analysis, or a combination thereof,” is used.
5.8.1 Vertical lift and in-flight refueling
Slightly reworded, but the same overall requirement with one significant deletion. The C applicability to “any man portable items that are carried internal to the aircraft” has been deleted.
5.8.3 Ordnance subsystems
Rewritten with two brand new sub-paragraphs that break out separately the pre-existing C requirement to withstand a 25 kV personnel ESD and adds a separate new requirement to withstand helicopter ESD (300 kV).
5.8.4 Electrical and electronic subsystems
Rewritten to refer to MIL-STD-461G (CS118) for test, whereas previously they had to point elsewhere.
5.9.3 Hazards of electromagnetic radiation to ordnance (HERO)
Rewritten to include ordnance safety margins that were struck from general margin paragraph 5.1.
5.14.2 Platform radiated emissions
Renamed from the same paragraph in C labeled 5.14.2 Inter-system EMC. The requirement has both greater generality and is more specific about what parameters need to be controlled. New sub-paragraph in D.
6.2 Acquisition requirements
Acquisition documents should specify the following: a. Title, number, and date of this standard.
6.3 DIDs
Not updated.
6.5 Key Words
Adds two new terms, electrostatic and HESD.
6.6 International standardization agreement implementation.
Rewritten slightly in D from the previous similar section 6.5 in C.
6.7 Acronyms
Replaces EMRADHAZ with RADHAZ.
Also, PESD and HESD are added.
6.8 Technical points of contact
Air Force and Army points-of-contact have been updated.
A.1.1 Scope
Includes extra language emphasizing that appendix is guidance only, not mandatory.
A.2.1.1 Specifications, standards, and handbooks
Slightly different wording. Also, the following additions, changes, and deletions:
- MIL-STD-1576, Electroexplosive Subsystem Safety Requirements and Test Methods for Space Systems—removed from applicable documents
- MIL-STD-3023 HEMP Protection for Military Aircraft—added
- MIL-STD-4023 HEMP Protection for Maritime Assets—added
- MIL-HDBK-83578 Criteria for Explosive Systems and Devices Used on Space Vehicles—deleted
NOTES:
*It must be noted that on certain naval platforms, there are radar systems (and unique modes of operation) that may produce fields in excess of those in Table IX, and MIL-HDBK-235 must be consulted to identify specific EME test requirements.
** In some of the frequency ranges for the “Restricted Average” column, limiting the exposure of personnel through time averaging will be required to meet the requirements of 5.9.1 for personnel safety.
TABLE IX: Maximum external EME levels for ordnance vs. -464C TABLE 9. Maximum external EME levels for ordnance.
-464D values first, -464C values second, where different. Red fill means level has increased. Yellow fill means change is less than 3 dB, either higher or lower, and blue fill means -464D level is lower than for -464C. * means no emitters in that frequency range.
A.2.1.2 Other Government documents, drawings, and publications
- Army, ATPD-2407 Electromagnetic Environmental Effects (E3) for U.S. Army Tank and Automotive Vehicle Systems Tailored from MIL-STD-464C—added
- TOP 01-2-511A US Army Test and Evaluation Command Test Operations Procedure—added
A.2.2 Non-Government Publications
- Institute of Electrical and Electronics (IEEE) Transactions on Electromagnetic Compatibility
- DOI:10.1109/TEMC.2016.2575842 Effect of Human Activities and Environmental Conditions on Electrostatic Charging—added
- Franklin Applied Physics
- F-C2560 RF Evaluation of the Single Bridgewire Apollo Standard Initiator—deleted
A.3 Acronyms
- AMITS air management information tracking system—deleted
- EMRADHAZ—deleted
- HESD helicopter-borne electrostatic discharge—added
- PESD personnel-borne electrostatic discharge—added
- RADHAZ Radiation hazards—added
A.4.1 Requirement Guidance
Adds Army ATPD-2407 and TOP 01-2-511A is EMC guidance and test procedures.
A.4.1.e Requirement Guidance
Includes additional guidance and a slightly different approach than C. Margin Requirement Guidance A.5.1 adds the non-italicized statement in the following excerpt:
This paragraph is deleted from this section in D (look for it in the EID section):
A.5.2 Intra-system EMC
Under Requirements Rationale, the final sentence in C:
is replaced by a more descriptive version in D:
A.5.2 Verification Guidance
The following and final line item is modified in D to read:
In C, line item h reads:
Table A-1 Type of EMI/EMC testing doesn’t exist in D.
A.5.3 Requirement Guidance
These words added to the very end of this section:
A.5.4 Requirement Guidance (HPM)
Eliminates Tables A-4 – A-10 from C and also calculation of some example problems using these tables.
A.5.4 Requirement Rationale (HPM)
Eliminates some wording questioning the effectiveness of HPM.
A.5.4 Verification Guidance (HPM)
Eliminates reference to these deleted examples in D.
A.5.6 Requirement Guidance (EMP)
Contains some extra description of HEMP composite environment. It also adds descriptions of EMP-related military standards for dealing with EMP, including effects on spacecraft.
A.5.6 Requirement Lessons Learned
Has this sentence in common with C:
But D adds this last sentence not in C:
A.5.6 Verification Rationale (EMP)
D replaces this C paragraph:
with this paragraph:
Note the emphasis on the cost of EMP design has been replaced with wording more conducive to getting EMP designs installed.
In the same section, this new D wording:
has been appended to this existing C wording:
A.5.7 Requirement Guidance (Subsystem & Equipment EMI)
Eliminates wording about DO-160 section 22 now that CS117 is available.
A.5.7.1 Portable Electronic Devices and Carry-On Equipment Requirements
All new appendix material. Basically refers to A.5.2. Intra-system EMC.
A.5.8.1 Vertical lift and in-flight refueling
Slightly rewritten, no changes.
A.5.8.3 Ordnance Subsystems
Greatly expanded and also includes the following new sections:
- A.5.8.3.1 Personnel-borne ESD (PESD) for ordnance and ordnance systems
- A.5.8.3.2 Helicopter-borne ESD (HESD) for ordnance and ordnance systems
A.5.9.3 Requirement Rationale (Ordnance RADHAZ (HERO)).
This section is rewritten with substantive changes.
A.5.9.3 Requirement Guidance (Ordnance RADHAZ (HERO))
This section is rewritten with substantive changes. MIL-STD-464C was:
The last sentence refers to measuring the rf TOS of bridgewires, and that has been completely debunked. This section now reads:
A.5.14.2 Requirement Rationale (Platform Radiated Emission)
Rewritten with added information.
A.5.15 Requirement Guidance (EM Spectrum Compatibility)
Completely rewritten.
A.5.15 Verification Rationale (EM Spectrum Compatibility)
Completely rewritten.
A.5.15 Verification Guidance (EM Spectrum Compatibility)
Added information.
- MIL-STD-464C is really MIL-STD-464B, but there was a release cycle error, and MIL-STD-464B was replaced after just a few months. The content didn’t change.
- Author’s note: The significant truncation is due to moving ordnance-related margins to their own separate section. The ordnance margins haven’t changed – this just represents a reorganization of the standard.