Heat Index calculations

Hey Smartsheet friends

I have one of "those" formulas i need to use in a calculation that uses quite a deep decimal placement. For those of your that are a bit geeky like me you will love this one!!!!

I am collected information on temperature and relative humidity and I need to calculate the heat index (it's part of a new OSHA rule). For those of you wondering, the calculation is…..

HI = -42.379 + 2.04901523*T + 10.14333127*RH - .22475541*T*RH - .00683783*T*T - .05481717*RH*RH + .00122874*T*T*RH + .00085282*T*RH*RH - .00000199*T*T*RH*RH

HI is Heat Index, T is temperature, and RH is Relative Humidity

I plug this calculation into my Smartsheet column and it changes the calculation to (i put in bold the changes to the calculation):

=(-42.379 + (2.04902 * Temperature@row ) + (10.14333 * [Relative Humidity]@row ) - (0.22476 * Temperature@row * [Relative Humidity]@row ) - (0.00684 * Temperature@row * Temperature@row ) - (0.05482 * [Relative Humidity]@row * [Relative Humidity]@row ) + (0.00123 * Temperature@row * Temperature@row * [Relative Humidity]@row ) + (0.00085 * Temperature@row * [Relative Humidity]@row * [Relative Humidity]@row ) - (0 * Temperature@row * Temperature@row * [Relative Humidity]@row * [Relative Humidity]@row ))

As you can see, my actual calculation changes and rounds to the 5th decimal space.

So at a temperature of 80 degrees F with a relative humidity of 40%, the heat index should be 79.9. However the calculation in Smartsheet shows 100.23580. Definitely a number I cannot use!

Is there a way to prevent this from happening?

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Accepted answers

KPH

Hi @AuRedneckPrincess

Thinking mathematically…How about scaling each value up by a factor of 10,000 and then dividing the result by 10,000?

That way none of the constants will have more than three decimal places, so will not be rounded. But the formula is mathematically equivalent.

=(-423790 + (20490.1523 * Temperature@row) + (101433.3127 * [Relative Humidity]@row) - (2247.5541 * Temperature@row * [Relative Humidity]@row) - (68.3783 * Temperature@row * Temperature@row ) - (548.1717 * [Relative Humidity]@row * [Relative Humidity]@row) + (12.2874 * Temperature@row * Temperature@row * [Relative Humidity]@row) + (8.5282 * Temperature@row * [Relative Humidity]@row * [Relative Humidity]@row) - (0.0199 * Temperature@row * Temperature@row * [Relative Humidity]@row * [Relative Humidity]@row) ) / 10000

Would that be a suitable workaround?

All comments

KPH

Hi @AuRedneckPrincess

Thinking mathematically…How about scaling each value up by a factor of 10,000 and then dividing the result by 10,000?

That way none of the constants will have more than three decimal places, so will not be rounded. But the formula is mathematically equivalent.

Would that be a suitable workaround?

AuRedneckPrincess

@KPH AWESOME!!!! It worked!!!!! Thank you so much. Never thought about scaling it up! You are a godsend!!!!! What few hairs i still have on my head thanks you!😁

KPH

Excellent news. Glad I could help.

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