1 Scope
This part of IEC 60079 specifies the construction and testing of intrinsically safe apparatus intended for use in an explosive atmosphere and for associated apparatus, which is intended for connection to intrinsically safe circuits which enter such atmospheres.
Modification of Clause 1, first paragraph as follows:
1.1 Replace "part of IEC 60079" with "standard".
This type of protection is applicable to electrical equipment in which the electrical circuits themselves are incapable of causing an explosion in the surrounding explosive atmospheres.
This standard is also applicable to electrical equipment or parts of electrical equipment located outside the explosive atmosphere or protected by another Type of Protection listed in IEC 60079-0, where the intrinsic safety of the electrical circuits in the explosive atmosphere may depend upon the design and construction of such electrical equipment or parts of such electrical equipment. The electrical circuits exposed to the explosive atmosphere are evaluated for use in such an atmosphere by applying this standard.
The requirements for intrinsically safe systems are provided in IEC 60079-25.
This standard supplements and modifies the general requirements of IEC 60079-0, except as indicated in . Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirements of this standard shall take precedence.
If requirements in this standard are applicable to both intrinsically safe apparatus and associated apparatus the term “apparatus” is used throughout the standard.
This standard is for electrical equipment only; therefore the term “equipment” used in the standard always means “electrical equipment”.
If associated apparatus is placed in the explosive atmosphere, it shall be protected by an appropriate Type of Protection listed in IEC 60079-0, and then the requirements of that method of protection together with the relevant parts of IEC 60079-0 also apply to the associated apparatus.
Table 1 Applicability of specific clauses of IEC 60079-0
Clause or subclause of IEC 60079-0
IEC 60079-0 clause application to
IEC 60079-11
Intrinsically safe apparatus
Associated apparatus
Ed. 5.0 (2007)
Ed. 6.0 (2011)
Clause / Subclause title
Group I and Group II
Group III
(informative)
(informative)
(normative)
1
1
Scope
Applies
Applies
Applies
2
2
Normative references
Applies
Applies
Applies
3
3
Terms and definitions
Applies
Applies
Applies
4
4
Equipment grouping
Applies
Applies
Applies
4.1
4.1
Group I
Applies
Excluded
Applies
4.2
4.2
Group II
Applies
Excluded
Applies
4.3
4.3
Group III
Excluded
Applies
Applies
4.4
4.4
Equipment for a particular explosive atmosphere
Applies
Applies
Applies
5.1
5.1
Environmental influences
Applies
Applies
Applies
5.1.1
5.1.1
Ambient temperature
Applies
Applies
Applies
5.1.2
5.1.2
External source of heating or cooling
Applies
Applies
Applies
5.2
5.2
Service temperature
Applies
Applies
Applies
5.3.1
5.3.1
Determination of maximum surface temperature
Applies
Applies
Excluded
5.3.2.1
5.3.2.1
Group I electrical equipment
Applies
Excluded
Excluded
5.3.2.2
5.3.2.2
Group II electrical equipment
Applies
Excluded
Excluded
5.3.2.3
5.3.2.3
Group III electrical equipment
Excluded
Applies
Excluded
5.3.3
5.3.3
Small component temperature for Group I or Group II electrical equipment
Applies
Excluded
Excluded
6.1
6.1
General
Applies
Applies
Applies
6.2
6.2
Mechanical strength of equipment
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
6.3
6.3
Opening times
Excluded
Excluded
Excluded
6.4
6.4
Circulating currents in enclosures (e.g. of large electrical machines)
Excluded
Excluded
Excluded
6.5
6.5
Gasket retention
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
6.6
6.6
Electromagnetic and ultrasonic radiating equipment
Applies
Applies
Excluded
7.1.1
7.1.1
Applicability
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.2
7.1.2.1
Specification of materials
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.3
7.1.2.2
Plastic materials
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.4
7.1.2.3
Elastomers
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.2
7.2
Thermal endurance
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.3
7.3
Resistance to light
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.4
7.4
Electrostatic charges on external non-metallic materials
Applies
Applies
Excluded
NR
7.5
Accessible metal parts
Applies
Applies
Excluded
7.5
NR
Threaded holes
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
8.1
8.1
Material composition
Applies
Applies
Excluded
8.1.1
8.2
Group I
Applies
Excluded
Excluded
8.1.2
8.3
Group II
Applies
Excluded
Excluded
8.1.3
8.4
Group III
Excluded
Applies
Excluded
8.2
NR
Threaded holes
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
9
9
Fasteners
Excluded
Excluded
Excluded
10
10
Interlocking devices
Excluded
Excluded
Excluded
11
11
Bushings
Excluded
Excluded
Excluded
12
12
Materials used for cementing
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
13
13
Ex Components
Applies
Applies
Applies
14
14
Connection facilities and termination compartments
Excluded
Excluded
Excluded
15
15
Connection facilities for earthing or bonding conductors
Excluded
Excluded
Excluded
16
16
Entries into enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
17
17
Supplementary requirements for rotating machines
Excluded
Excluded
Excluded
18
18
Supplementary requirements for switchgear
Excluded
Excluded
Excluded
19
19
Supplementary requirements for fuses
Excluded
Excluded
Excluded
20
20
Supplementary requirements for plugs, socket outlets and connectors
Excluded
Excluded
Excluded
21
21
Supplementary requirements for luminaires
Excluded
Excluded
Excluded
22
22
Supplementary requirements for caplights and handlights
Modified
Modified
Excluded
23.1
23.1
General
Applies
Applies
Applies
23.2
23.2
Batteries
Excluded
Excluded
Excluded
23.3
23.3
Cell types
Applies
Applies
Applies
23.4
23.4
Cells in a battery
Applies
Applies
Applies
23.5
23.5
Ratings of batteries
Applies
Applies
Applies
23.6
23.6
Interchangeability
Applies
Applies
Applies
23.7
23.7
Charging of primary batteries
Applies
Applies
Applies
23.8
23.8
Leakage
Applies
Applies
Applies
23.9
23.9
Connections
Applies
Applies
Applies
23.10
23.10
Orientation
Applies
Applies
Applies
23.11
23.11
Replacement of cells or batteries
Applies
Applies
Applies
23.12
23.12
Replaceable battery pack
Applies
Applies
Applies
24
24
Documentation
Applies
Applies
Applies
25
25
Compliance of prototype or sample with documents
Applies
Applies
Applies
26.1
26.1
General
Applies
Applies
Applies
26.2
26.2
Test configuration
Applies
Applies
Applies
26.3
26.3
Tests in explosive test mixtures
Applies
Applies
Applies
26.4.1
26.4.1
Order of tests
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.1
26.4.1.1
Metallic enclosures, metallic parts of enclosures and glass parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.2
26.4.1.2
Non-metallic enclosures or non-metallic parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.2.1
26.4.1.2.1
Group I electrical equipment
Excluded except when 3 a) is applied
Excluded
Excluded except when 3 a) is applied
26.4.1.2.2
26.4.1.2.2
Group II and Group III electrical equipment
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.2
26.4.2
Resistance to impact
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.3
26.4.3
Drop test
Applies
Applies
Excluded except when 3 a) is applied
26.4.4
26.4.4
Acceptance criteria
Applies
Applies
Excluded except when 3 a) is applied
26.4.5
26.4.5
Degree of protection (IP) by enclosures
Applies
Applies
Applies
26.5.1.1
26.5.1.1
General
Applies
Applies
Excluded
26.5.1.2
26.5.1.2
Service temperature
Modified
Modified
Modified
26.5.1.3
26.5.1.3
Maximum surface temperature
Modified
Modified
Modified
26.5.2
26.5.2
Thermal shock test
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.5.3
26.5.3
Small component ignition test (Group I and Group II)
Applies
Excluded
Excluded
26.6
26.6
Torque test for bushings
Excluded
Excluded
Excluded
26.7
26.7
Non-metallic enclosures or non-metallic parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.8
26.8
Thermal endurance to heat
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.9
26.9
Thermal endurance to cold
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.10
26.10
Resistance to light
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.11
26.11
Resistance to chemical agents for Group I electrical equipment
Excluded except when 3 a) is applied
Excluded
Excluded
26.12
26.12
Earth continuity
Excluded
Excluded
Excluded
26.13
26.13
Surface resistance test of parts of enclosures of non-metallic materials
Applies
Applies
Excluded
26.15
26.14
Measurement of capacitance
Applies
Applies
Excluded
NR
26.15
Verification of ratings of ventilating fans
Excluded
Excluded
Excluded
NR
26.16
Alternative qualification of elastomeric sealing O-rings
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
27
27
Routine tests
Applies
Applies
Applies
28
28
Manufacturer’s responsibility
Applies
Applies
Applies
29
29
Marking
Applies
Applies
Applies
30
30
Instructions
Applies
Applies
Applies
Annex A (Normative)
Annex A (Normative)
Supplementary requirements for cable glands
Excluded
Excluded
Excluded
Annex B (Normative)
Annex B (Normative)
Requirements for Ex Components
Applies
Applies
Applies
Annex C (Normative)
Annex C (Normative)
Example of rig for resistance to impact test
Applies
Applies
Excluded except when 3 a) is applied
Annex D (Informative)
NR
Alternative risk assessment method encompassing “equipment protection levels” for Ex equipment
Applies
Applies
Applies
Annex E (Informative)
Annex D (Informative)
Motors supplied by converters
Excluded
Excluded
Excluded
NR
Annex E (Informative)
Temperature rise testing of electric machines
Excluded
Excluded
Excluded
NR
Annex F (Informative)
Guideline flowchart for tests of non-metallic enclosures or nonmetallic parts of enclosures (26.4)
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
Applies – This requirement of IEC 60079-0 is applied without change.
Excluded – This requirement of IEC 60079-0 does not apply.
Excluded except – This requirement of IEC 60079-0 does not apply except when the conditions stated are met.
Modified – This requirement of IEC 60079-0 is modified as detailed in this standard.
NR – No requirements.
NOTE The clause numbers in the above table are shown for information only. The applicable requirements of IEC 60079-0 are identified by the clause title which is normative. This table was written against the specific requirements of IEC 60079-0, ed. 6.0. The clause numbers for the previous edition are shown for information only. This is to enable the General requirements IEC 60079-0, ed. 5.0, to be used where necessary with this part of IEC 60079. Where there were no requirements, indicated by NR, or there is a conflict between requirements, the later edition requirements take precedence.
Modification of Table 1DV NOTE to replace with the following:
Table 1DV Applicability of specific clauses of IEC 60079-0
Clause or subclause of IEC 60079-0
IEC 60079-0 clause application to
IEC 60079-11
Intrinsically safe apparatus
Associated apparatus
Ed. 5.0
Ed. 6.0
Clause / Subclause title
Group I and Group II
Group III
(informative)
(informative)
(normative)
1
1
Scope
Applies
Applies
Applies
2
2
Normative references
Applies
Applies
Applies
3
3
Terms and definitions
Applies
Applies
Applies
4
4
Equipment grouping
Applies
Applies
Applies
4.1
4.1
Group I
Applies
Excluded
Applies
4.2
4.2
Group II
Applies
Excluded
Applies
4.3
4.3
Group III
Excluded
Applies
Applies
4.4
4.4
Equipment for a particular explosive atmosphere
Applies
Applies
Applies
5.1
5.1
Environmental influences
Applies
Applies
Applies
5.1.1
5.1.1
Ambient temperature
Applies
Applies
Applies
5.1.2
5.1.2
External source of heating or cooling
Applies
Applies
Applies
5.2
5.2
Service temperature
Applies
Applies
Applies
5.3.1
5.3.1
Determination of maximum surface temperature
Applies
Applies
Excluded
5.3.2.1
5.3.2.1
Group I electrical equipment
Applies
Excluded
Excluded
5.3.2.2
5.3.2.2
Group II electrical equipment
Applies
Excluded
Excluded
5.3.2.3
5.3.2.3
Group III electrical equipment
Excluded
Applies
Excluded
5.3.3
5.3.3
Small component temperature for Group I or Group II electrical equipment
Applies
Excluded
Excluded
6.1
6.1
General
Applies
Applies
Applies
6.2
6.2
Mechanical strength of equipment
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
6.3
6.3
Opening times
Excluded
Excluded
Excluded
6.4
6.4
Circulating currents in enclosures (e.g. of large electrical machines)
Excluded
Excluded
Excluded
6.5
6.5
Gasket retention
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
6.6
6.6
Electromagnetic and ultrasonic radiating equipment
Applies
Applies
Excluded
7.1.1
7.1.1
Applicability
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.2
7.1.2.1
Specification of materials
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.3
7.1.2.2
Plastic materials
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.1.4
7.1.2.3
Elastomers
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.2
7.2
Thermal endurance
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.3
7.3
Resistance to light
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
7.4
7.4
Electrostatic charges on external non-metallic materials
Applies
Applies
Excluded
NR
7.5
Accessible metal parts
Applies
Applies
Excluded
7.5
NR
Threaded holes
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
8.1
8.1
Material composition
Applies
Applies
Excluded
8.1.1
8.2
Group I
Applies
Excluded
Excluded
8.1.2
8.3
Group II
Applies
Excluded
Excluded
8.1.3
8.4
Group III
Excluded
Applies
Excluded
8.2
NR
Threaded holes
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
9
9
Fasteners
Excluded
Excluded
Excluded
10
10
Interlocking devices
Excluded
Excluded
Excluded
11
11
Bushings
Excluded
Excluded
Excluded
12
12
Materials used for cementing
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
13
13
Ex Components
Applies
Applies
Applies
14
14
Connection facilities and termination compartments
Excluded
Excluded
Excluded
15
15
Connection facilities for earthing or bonding conductors
Excluded
Excluded
Excluded
16
16
Entries into enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
17
17
Supplementary requirements for rotating machines
Excluded
Excluded
Excluded
18
18
Supplementary requirements for switchgear
Excluded
Excluded
Excluded
19
19
Supplementary requirements for fuses
Excluded
Excluded
Excluded
20
20
Supplementary requirements for plugs, socket outlets and connectors
Excluded
Excluded
Excluded
21
21
Supplementary requirements for luminaires
Excluded
Excluded
Excluded
22
22
Supplementary requirements for caplights and handlights
Modified
Modified
Excluded
23.1
23.1
General
Applies
Applies
Applies
23.2
23.2
Batteries
Excluded
Excluded
Excluded
23.3
23.3
Cell types
Applies
Applies
Applies
23.4
23.4
Cells in a battery
Applies
Applies
Applies
23.5
23.5
Ratings of batteries
Applies
Applies
Applies
23.6
23.6
Interchangeability
Applies
Applies
Applies
23.7
23.7
Charging of primary batteries
Applies
Applies
Applies
23.8
23.8
Leakage
Applies
Applies
Applies
23.9
23.9
Connections
Applies
Applies
Applies
23.10
23.10
Orientation
Applies
Applies
Applies
23.11
23.11
Replacement of cells or batteries
Applies
Applies
Applies
23.12
23.12
Replaceable battery pack
Applies
Applies
Applies
24
24
Documentation
Applies
Applies
Applies
25
25
Compliance of prototype or sample with documents
Applies
Applies
Applies
26.1
26.1
General
Applies
Applies
Applies
26.2
26.2
Test configuration
Applies
Applies
Applies
26.3
26.3
Tests in explosive test mixtures
Applies
Applies
Applies
26.4.1
26.4.1
Order of tests
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.1
26.4.1.1
Metallic enclosures, metallic parts of enclosures and glass parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.2
26.4.1.2
Non-metallic enclosures or non-metallic parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.1.2.1
26.4.1.2.1
Group I electrical equipment
Excluded except when 3 a) is applied
Excluded
Excluded except when 3 a) is applied
26.4.1.2.2
26.4.1.2.2
Group II and Group III electrical equipment
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.2
26.4.2
Resistance to impact
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.4.3
26.4.3
Drop test
Applies
Applies
Excluded except when 3 a) is applied
26.4.4
26.4.4
Acceptance criteria
Applies
Applies
Excluded except when 3 a) is applied
26.4.5
26.4.5
Degree of protection (IP) by enclosures
Applies
Applies
Applies
26.5.1.1
26.5.1.1
General
Applies
Applies
Excluded
26.5.1.2
26.5.1.2
Service temperature
Modified
Modified
Modified
26.5.1.3
26.5.1.3
Maximum surface temperature
Modified
Modified
Modified
26.5.2
26.5.2
Thermal shock test
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.5.3
26.5.3
Small component ignition test (Group I and Group II)
Applies
Excluded
Excluded
26.6
26.6
Torque test for bushings
Excluded
Excluded
Excluded
26.7
26.7
Non-metallic enclosures or non-metallic parts of enclosures
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.8
26.8
Thermal endurance to heat
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.9
26.9
Thermal endurance to cold
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.10
26.10
Resistance to light
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
26.11
26.11
Resistance to chemical agents for Group I electrical equipment
Excluded except when 3 a) is applied
Excluded
Excluded
26.12
26.12
Earth continuity
Excluded
Excluded
Excluded
26.13
26.13
Surface resistance test of parts of enclosures of non-metallic materials
Applies
Applies
Excluded
26.15
26.14
Measurement of capacitance
Applies
Applies
Excluded
NR
26.15
Verification of ratings of ventilating fans
Excluded
Excluded
Excluded
NR
26.16
Alternative qualification of elastomeric sealing O-rings
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
27
27
Routine tests
Applies
Applies
Applies
28
28
Manufacturer’s responsibility
Applies
Applies
Applies
29
29
Marking
Applies
Applies
Applies
30
30
Instructions
Applies
Applies
Applies
Annex A (Normative)
Annex A (Normative)
Supplementary requirements for cable glands
Excluded
Excluded
Excluded
Annex B (Normative)
Annex B (Normative)
Requirements for Ex Components
Applies
Applies
Applies
Annex C (Normative)
Annex C (Normative)
Example of rig for resistance to impact test
Applies
Applies
Excluded except when 3 a) is applied
Annex D (Informative)
NR
Alternative risk assessment method encompassing “equipment protection levels” for Ex equipment
Applies
Applies
Applies
Annex E (Informative)
Annex D (Informative)
Motors supplied by converters
Excluded
Excluded
Excluded
NR
Annex E (Informative)
Temperature rise testing of electric machines
Excluded
Excluded
Excluded
NR
Annex F (Informative)
Guideline flowchart for tests of non-metallic enclosures or nonmetallic parts of enclosures (26.4)
Excluded except when 3 a) is applied
Excluded except when 3 a) is applied.
Excluded except when 3 a) is applied
Applies – This requirement of IEC 60079-0 is applied without change.
Excluded – This requirement of IEC 60079-0 does not apply.
Excluded except – This requirement of IEC 60079-0 does not apply except when the conditions stated are met.
Modified – This requirement of IEC 60079-0 is modified as detailed in this standard.
NR – No requirements.
NOTE 1 The clause numbers in the above table are shown for information only. The applicable requirements of IEC 60079-0 are identified by the clause title which is normative. This table was written against the specific requirements of IEC 60079-0, ed. 6.0. The clause numbers for the previous edition are shown for information only. This is to enable the General requirements IEC 60079-0, ed. 5.0, to be used where necessary with this part of IEC 60079. Where there were no requirements, indicated by NR, or there is a conflict between requirements, the later edition requirements take precedence.
NOTE 2 In the US, the authority having jurisdiction for underground mines is the Mine Safety and Health Administration (MSHA) of the federal government. Additional regulations beyond those detailed here will also apply.
Addition of 1DV.2.1
1.1 Where references are made to other IEC 60079 standards, the referenced requirements found in these standards shall apply as modified by any applicable U.S. National Differences.