Temperature Adjustment when ME EQUIPMENT is rated for used at Higher Altitudes

Roland chung

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Hello folks,

Sub-clause 11.1.3 of IEC 60601-1/ A1 discussed a topic about whether it would be appropriate to reduce the maximum allowable temperature for surfaces and APPLIED PARTS at higher altitudes (> 2000 m).

It is recognized that a reduction in air pressure has the effect of raising the ambient temperature by 1 ºC per 300 m elevation. However, the temperature limits of IEC 60601-1 have generally been found to be adequate for ME EQUIPMENT used at up to 2000 m (i.e. there are no reports indicating that burns have occurred at altitudes approaching 2000 m). Furthermore, at altitudes exceeding 2000 m the ambient air temperature will virtually always be well below the 25 ºC at which test measurements would be made (the ambient at which ME EQUIPMENT is highly unlikely to exceed 25 ºC at altitudes above 2 000 m). Therefore, where ME EQUIPMENT is rated for used at higher altitudes, measurements made at 25 ºC can be adjusted by 1º C per 300 m above 2000 m, however where this is done the maximum ambient temperature (at such altitudes) is assumed to be 25º C (no further adjustment is made to the readings to compensate for rated ambient temperatures above 25 ºC). Because this is considered an extremely unique situation and that the lower ambient temperatures found at such altitudes are likely to offset the resulting increase in measured temperatures of surfaces, no modifications to the normative text were deemed appropriate.

I have some confusion about the rationale mentioned above.

1) In regard to reduction in air pressure has the effect of raising the ambient temperature by 1 ºC per 300 m elevation, is this in compliance with the logic? From common sense, higher the altitude, lower the air pressure and also lower the ambient temperature. (From memory, reduce the ambient by 0.6 ºC per 100 m elevation).

2) From the rationale, temperature measurements made at 25 ºC can be adjusted by 1º C per 300 m above 2000 m (this is done the maximum ambient temperature (at such altitudes) is assumed to be 25º C). If ME equipment is rated for used at 3000 m and temperature measurements made at 25 ºC (test site altitude < 2000 m), is it necessary to correct the measured temperature by 3.3 º C (1000 m elevation)?

Please kindly share your knowledge.

Thanks and kind regards,
Roland
 

Stijloor

Leader
Super Moderator
Hello folks,

Sub-clause 11.1.3 of IEC 60601-1/ A1 discussed a topic about whether it would be appropriate to reduce the maximum allowable temperature for surfaces and APPLIED PARTS at higher altitudes (> 2000 m).



I have some confusion about the rationale mentioned above.

1) In regard to reduction in air pressure has the effect of raising the ambient temperature by 1 ºC per 300 m elevation, is this in compliance with the logic? From common sense, higher the altitude, lower the air pressure and also lower the ambient temperature. (From memory, reduce the ambient by 0.6 ºC per 100 m elevation).

2) From the rationale, temperature measurements made at 25 ºC can be adjusted by 1º C per 300 m above 2000 m (this is done the maximum ambient temperature (at such altitudes) is assumed to be 25º C). If ME equipment is rated for used at 3000 m and temperature measurements made at 25 ºC (test site altitude < 2000 m), is it necessary to correct the measured temperature by 3.3 º C (1000 m elevation)?

Please kindly share your knowledge.

Thanks and kind regards,
Roland

A Quick Bump.

Can someone help Roland with this?

Thank you very much!!

Stijloor.
 
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