Air Techniques, Inc
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Page 26
Electromagnetic resistance to interference for non life-supporting appliances or systems
Portable and cordless radio appliances should not be used close to the appliance, including any elec-
trical supply lines, as the recommended safety distance which has been calculated from the transmis-
sion frequency
Resistance to
interference
checks
IEC 60601 - test
levels
Level of
consistency
Recommended safety distance
Conductive HF
interference factor
according to
IEC 61000-4-6
3 V
eff
150 kHz to
80 MHz
[V
1
] V
d = [35 / V
1
]
⋅ √
P
d = 12
⋅ √
P
Radiated HF in-
terference factor
according to
IEC 61000-4-3
3 V/m 80 MHz to
25 GHz
[E
1
] V/m
d = [35 / E
1
]
⋅ √
P for 80 MHz to 800
MHz
d = 12
⋅ √
P for 80 MHz to 800 MHz
d = [7 / E
1
]
⋅ √
P for 800 MHz to 25
GHz
d = 23
⋅ √
P for 800 MHz to 25 GHz
Table 3: Electromagnetic resistance to interference for non life-supporting appliances or systems
P
Rated power of transmitter in watts (W) according to manufacturer's information
d
Recommended safety distance in metres (m)
The field strength of stationary radio transmitters for all frequencies must be, according to
investigation carried out on-site
a
lower than the consistency level
b
Some interference is possible in environments surrounding appliances where the following
symbol is present
Note 1
Where 80 MHz and 800 MHz are present, the higher frequency range becomes
valid
Note 2
These guidelines are not applicable for all possible situations The exact amount
of electro-magnetic transmissions can be considerably influenced by the rate of
absorption and reflection within the building, and the presence of objects and
people
a
The field strength of stationary transmitters, eg base station of radio telephones or cordless land-
line phones, amateur radio stations, on AM and FM radio or TV, cannot be theoretically exactly calcu-
lated in advance In order to establish the electromagnetic environment taking these stationary trans-
mitters into account, a study of the electromagnetic phenomena of the actual location must be under-
taken If the field strength measured at the location where the appliance is used exceeds the above
level of consistency, the appliance should be observed in order to demonstrate the intended function
If any unusual behaviour of the appliance is observed, additional steps will be required, eg changing
the orientation or location of the appliance
b
The field strength is less than [V
1
] V/m over the frequency range of 150 kHz to 80 MHz
Annex
