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firestar967  
#1 Posted : 12 November 2012 11:40:11(UTC)
Rank: Forum user
firestar967

I need a quick responce on this one please does anybody know if there is a set definition for a cold freezing temperature (i.e. Below 3 degrees). I don't believe that there is but I could be wrong. This is in regards to working in extreme weather conditions.
bilbo  
#2 Posted : 12 November 2012 13:19:10(UTC)
Rank: Super forum user
bilbo

The freezing temperature of water is that point at which water changess from a liquid state to solid one, normally considered to be 0 degrees C or 32 degrees Fahrenheit. Other liquids freeze at different temperatures.
safetyamateur  
#3 Posted : 12 November 2012 13:24:28(UTC)
Rank: Super forum user
safetyamateur

Sorry, can't help firestar. But wonder whether cold is dependent on other factors like heat is; in particular humidity.
colinreeves  
#4 Posted : 12 November 2012 13:35:49(UTC)
Rank: Super forum user
colinreeves

safetyamateur wrote:
Sorry, can't help firestar. But wonder whether cold is dependent on other factors like heat is; in particular humidity.


Totally agree. Recall working in Leningrad when temperature got up to -20 degrees at the warmest time of day - did not feel too bad because of low humidity. Still, I did not touch any metal parts!

JJ Prendergast  
#5 Posted : 12 November 2012 13:42:44(UTC)
Rank: Super forum user
JJ Prendergast

Strictly freezing (and boiling points) are also related to the air pressure.

i.e. high pressure = lower freezing point
Clairel  
#6 Posted : 12 November 2012 13:45:54(UTC)
Rank: Super forum user
Clairel

Definition in relation to what? Health and Safety Legislation or science?
firestar967  
#7 Posted : 12 November 2012 14:01:50(UTC)
Rank: Forum user
firestar967

Thanks for the replies and it answers my question, it was in regards to health and safety and working environment. Just someone had assigned a specific value that I did not think applied and rightly so by the looks of it (taking into consideration humidy, wind speed, wind chill, ground temperature, etc.).
Graham Bullough  
#8 Posted : 12 November 2012 14:15:48(UTC)
Rank: Super forum user
Graham Bullough

firestar

As bilbo suggests, a common definition for a freezing temperature is any temperature at or below 0 degrees Centigrade, i.e. capable of causing water to freeze. However, as your query appears to relate to people working outside in cold weather conditions, humidity, air pressure and the speed of any wind are also important factors regarding how people can be affected. For example, I find damp/humid air just above freezing point (a fairly common condition in parts of the UK during the winter months) notably more uncomfortable than dry air at down to minus 10C or more which I've often experienced during winter trips in Norway. Also, people will differ in their physical and psychological perceptions of cold weather, partly through what they are accustomed to, the nature and quality of their clothing and whether or not their work involves physical exercise which keeps their body temperature up.

As an example of how people differ in their perception of temperature, I remember being intrigued during a holiday in Southern Africa in June several years ago to see quite a number of local people wearing coats, hats, etc because they felt cold during what was their winter season even though the members of my group found it quite comfortable for wearing light summer clothing. Evidently, the locals were more accustomed to the high temperatures of their summer season which visitors from temperate countries like the UK try to avoid as being too hot.

Also, if some pedantry is allowed, it could be argued that weather with temperatures hovering above and below freezing point is far from 'extreme'. Seekers of extreme cold should try heading for the Arctic or Antarctic! :-)
stevedm  
#9 Posted : 13 November 2012 16:24:24(UTC)
Rank: Super forum user
stevedm

Fire...

one of the reasons it is set at -3 deg C is that this is the air temperature that skin starts to freeze at...

johnmurray  
#10 Posted : 13 November 2012 19:51:30(UTC)
Rank: Super forum user
johnmurray

JJ Prendergast wrote:
Strictly freezing (and boiling points) are also related to the air pressure.

i.e. high pressure = lower freezing point


By about one hundredth of a degree per atmosphere of pressure...
firesafety101  
#11 Posted : 13 November 2012 21:54:04(UTC)
Rank: Super forum user
firesafety101

You could ask a brass monkey :-)
Phil Grace  
#12 Posted : 14 November 2012 12:33:45(UTC)
Rank: Super forum user
Phil Grace

I'm not a weatherman but temperature alone will not suffice.

As one poster has mentioned humidity has an impact on the temperature that can be dealt with.

Perhaps far more importnat is wind chill. A strong wind can lower/reduce the "temperature" experienced by many degrees. Thus a temp that is quite acceptable on a still day can be unacceptable if wind is blowing. Doubt you can come up with a temperature based limit.

Phil
Graham Bullough  
#13 Posted : 14 November 2012 14:04:21(UTC)
Rank: Super forum user
Graham Bullough

To add to Phil's information about wind chill there are charts with different types of unit for wind speed and temperature readily available from the internet (try searching under "wind chill chart") to show how temperature is effectively reduced as wind speed increases, e.g air with a temperature of 0 deg C on a still day is reduced to about minus 13 deg C by a wind speed of 20mph. Some charts include coloured zones with specific time periods within which the average person would be susceptible to sustaining frostbite in exposed skin.

As very few people have anemometers to measure outdoor wind speeds, the main purpose of the charts for most people is evidently to show/remind them just how increasing wind speed can significantly reduce temperature. Also some charts are supplemented by useful tips on how to keep skin covered and minimise suscepibility to frostbite, etc.

On a general note people engaged in outdoor work or leisure activities in cold conditions should try to remain aware of prevailing conditions, including increases in wind speeds and/or direction, (i.e. make dynamic risk assessments) and be ready to decide when conditions have become sufficiently adverse for them to prudently modify what they're doing or even find shelter/go indoors if feasible.
Hutchison43088  
#14 Posted : 14 November 2012 15:36:48(UTC)
Rank: Forum user
Hutchison43088

Used to have 5 Degrees and -5 degrees and below for clothing levels when working in cold storage, ie big fridges and freezers in previous role years ago

Last site I worked it it was under 10 degrees with different clothing levels offered the lower the temperature. Not aware of a defined temp other than workplace temp guidelines. Came down to company risk assessments and policies to be followed.
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