# New NFI App

**Finally, after months of delays, the NFI App is ready!**

However, there is one little wrinkle. There are a couple of differences between the Android and Apple versions of the app. The Android version is available right now. The Apple version should be ready by the end of the week or very early next week.

**Android devices:** Go to Google Play and search for "NFI App". You can download the app for free. You get the Corner Clearance formula with the free version and it costs 99 cents to activate the other four formulas.

**Apple devices:** Go to the App store, search for "NFI App". It will cost 99 cents to download the app but that gets you all five formulas.

The app makes the five most commonly used mathematical formulas used by hearth appliance installers much easier and quicker to process.

**Corner Installation Calculator**

Setting a free standing stove in place for a corner installation usually means a series of several little moves in order to maintain the proper clearances. This formula makes it simple. Enter the corner clearance requirement, the width and the depth of the stove. The resulting number will be how far out from the corner the front of the stove should be.

**Hole Size Calculator**

Figuring out the right size hole to cut depends on the pitch of the roof. Simply enter the Rise, Run and the diameter of the pipe plus the clearance on both sides to find an accurate size hole.

**Pitched Roof Chimney Height Calculator**

This formula enables you to meet the 3'/2'/10' for chimney height. Simply enter the rise, the distance to the peak and the height of any object within 10'. The result will be the height the chimney needs to be to meet the requirements specified in NFPA 211.

**Extension Calculations for Cathedral Ceilings**

Since single and double wall connector pipe have greater clearances than factory-built chimney pipe, the chimney must hang down into the room when installed in a cathedral ceiling. Simply enter the diameter of the chimney pipe, the diameter of the connector pipe, the clearance required to the connector pipe, the rise and the run. The result will be the length of chimney pipe that must hang down into the room.

**Combustion Air Calculations for Gas Appliances**

The Known Air Infiltration Rate (KAIR) formula helps determine the combustion air requirements if the Air Change per Hour (ACH) is known. The KAIR method must be used if the ACH is known to be less than 0.40. Simply enter the BTU input of the appliance and the ACH to determine the minimum cubic feet required for that appliance.

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