## Elevator

### 1- Calculate the Crack Length (which cause the leakage of air flow)

##### 2- Calculate The Leakage Area

**Table (1.1) Standard Leakage Area**

##### 3- Air Leakage

∆P: difference pressure between elevator and outside space which equal 50 Pa (Maximum 60 Pa). Leakage Area: Total area for all doors.

4- Multiply Air Leakage by Safety Factor (25%)

### Elevator Pressurization Calculation Example

One Door (Lift Landing) with 0.9m width (Height as standard is equal 2.1 m)

##### 1- Crack Length

=2H+2W

=6m

##### 2- The Leakage Area =

##### 3- Air Leakage

4- Take 25% Factor of Safety

## Staircase pressurization

-Pressurization System: Control the smoke by pressure difference, to make sure that the smoke will not leak to stairwell.

Wind Effect:

Smoke Feedback:

Design Pressure Difference:

###### (F MAX= 133N), to calculate the force:

**Table (1.2): Pressure design Difference (NFPA 92,2012)**

Type of Stairwell Pressurization:

**“CFM = (300-550) Per floor”**

-Multiple Injection (One Fan or more)

- Fan Location: The stairwell pressurization fan can be located anywhere, but since the entry/exit doors at ground level will remain open during emergency for fire personnel entry as well refuge escape operations, the top location is preferred to avoid the short-circuiting of the air.

## Calculations

Flow rate leak by crack of doors and by open doors (if there is any door open), so we will calculate the air flow rate in two steps :

##### Step one: Calculate Leakage air flow rate We need:

Door dimensions (W*L)

Door Leakage length (By Excel Sheet)

Number of doors

By Excel sheet, calculate the total leakage area for doors.

Then using 𝑄 = 0.827 𝑥 𝐴 𝑥 𝑉 𝑥 P^(1/2) (m^3 /s) (By Excel Sheet)

##### Step two: Calculate Leakage air flow from open doors

Number of open doors

Using 𝑄 = 𝐴 𝑥 𝑉 (m^3 /s) (By Excel Sheet)

##### Final Step: Total Air flow rate

𝑄 = 𝑄1 + 𝑄2

Add 25% factor of safety

### Stair Pressurization Calculations :

Stair cases will be provided with pressurization fans to pressurize the stair wells in case of emergency as follows :

Escape Door Dimensions = 2.1 x 1.05 m

Escape Door Leakage Length = ( 2.1 + 1.05 ) x 2 =

= 6.3 m

Total Number of Doors = 10 Doors

So, The total doors actual leakage area =

= 10 x 0.01 x 6.3 ÷ 5.6 = 0.11 m²

So, Q1 = 0.827 x 0.113 x 50 ½ = 0.66 m^3 /s

= 1394 cfm

Assume 3 doors are fully opened during fire mode;

So, Q = 2.205 x 0.75 x 3 = m^3 /s = cfm

Total air flow rate = Q1 + Q2 = 1394 + 10512 = 11906 cfm

Assume 25% Safety Factor :

So, Q = 11906.3 x 1.25 = 14883 cfm

## Comments