The permeability number is illustrated by the image below.

To compute for the permeability number, five essential parameters are needed and these parameters are **Volume of Air (V), Height of the Specimen (H), Cross-sectional Area (A), Air Pressure (P)** and** Time (t).**

The formula for calculating permeability number:

P_{N} = ^{VH}/_{APt}

Where:

P_{N} = Permeability Number

V = Volume of Air

H = Height of the Specimen

A = Cross-sectional Area

P = Air Pressure

t = Time

Let’s solve an example;

Find the permeability number when the volume of air is 2, the height of the specimen is 7, the cross-sectional area is 3, the air pressure is 9 and the time is 4.

This implies that;

V = Volume of Air = 2

H = Height of the Specimen = 7

A = Cross-sectional Area = 3

P = Air Pressure = 9

t = Time = 4

P_{N} = ^{VH}/_{APt}

P_{N} = ^{(2)(7)}/_{(3)(9)(4)}

P_{N} = ^{(14)}/_{(108)}

P_{N} = 0.129

Therefore, the **permeability number **is **0.129.**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the permeability number.

To get the answer and workings of the permeability number using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

**Android (Paid)** – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)** – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)** – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Materials and Metallurgical **under **Engineering****.**

Now, Click on **Refractories**** **under **Materials and Metallurgical**

Now, Click on **Permeability Number** under **Refractories**

The screenshot below displays the page or activity to enter your values, to get the answer for the permeability number according to the respective parameter which is the **Volume of Air (V), Height of the Specimen (H), Cross-sectional Area (A), Air Pressure (P)** and** Time (t).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Volume of Air (V)** is **2**,** Height of the Specimen (H)** is **7**,** Cross-sectional Area (A)** is **3**,** Air Pressure (P) **is **9** and** Time (t)** is **4**.

Finally, Click on Calculate

As you can see from the screenshot above, **Nickzom Calculator**– The Calculator Encyclopedia solves for the permeability number and presents the formula, workings and steps too.