The H-Factor

Reducing Entropy

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Recently our previous blog service (Typepad) ended their business – so, we have a new home. It will take a bit to get images back and displaying properly, but we are working on it! Final pageview count of original Typepad blog: 387,232

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Using a Non-Standard Pipe Type in HydraCALC

A customer called today asking how to enter a 1″ black plastic underground pipe for the calc. This particular situation sounded unique enough that I did not tell him to add that pipe type to our database, as I would have if he expected to see this pipe type used repeatedly. I told him to…

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Using the Hydratec Software Download Area

Hydratec uses ShareFile to distribute our software installs and updates. New customers, or those without access, must request access to be able to get at these downloads. Access is only available to customers with a Hydratec subscription or those on an update plan. You can access the download area and request access by picking the…

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July 2023
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Fitting Lengths in HydraCALC – Why don’t they match what’s in the database?

This from a customer in Sweden (paraphrased). This in metric, but the math is the same in US units:

On the Fittings Used Summary, it says that a 65mm Tee has the equivalent pipe length 3.8m but in the calculation says 7.497m. And it´s the same for a 65mm 90 degree screwed elbow…the equivalent pipe length says 0.88m but in the final calculation on page 4 it says 1,736m

Why are these numbers different? And how can we change so that they are the same?

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The answer lies in NFPA (where else?).

Paragraph 22.4.3.1.3.1 of NFPA13:2010 states that for internal diameters other than Schedule 40 steel pipe the equivalent lengths given in Table 22.4.3.1.1 must be adjusted according to the formula given in that paragraph. The next paragraph (22.4.3.1.3.2) states that this new value must be further adjusted by the C-Factor if no C=120. Fittings whose values are supplied by a manufacturer that has already adjusted them do not need to be further adjusted.

These two adjustments change the equivalent length stored in HydraCALC's Pipe/Fittings data. So, these two calculation reports the customer is referring to often display different values.

This can be turned off, however, for those jurisdictions that do not require such an adjustment, or for fittings that have already been adjusted by the manufacturer.

When the job is calculated, you can deselect the Auto Adjust Fittings Lengths option. This will give you the stored database values:

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This option resets itself with each calculation, but you can turn that option off by default by using the Edit User Options tool in the Options drop down menu:

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Set the Auto Adjust Fittings option to False

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This adjustment can also be blocked when inputting new pipe and fittings into the Pipe/Fittings data. The highlighted column is named Y/N Mark. An 'N'' means to not adjust the fitting as mentioned above. This is most prevalent with CPVC fittings, as the manufacturers publish values that take the pipe diameter into account.

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Additional information can be found in this blog post: How Fitting Equivalent Length Modifiers Work

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