The question "How to calculate force NFF tertification poultry broilers house" is interpreted as a request to calculate the airflow rate or ventilation requirements for a poultry broiler house. In

Ventilation in a broiler house is essential for:

• Removing excess heat generated by the birds.
• Controlling humidity by removing moisture.
• Expelling harmful gases such as ammonia ($\text{NH}_3$) and carbon dioxide ($\text{CO}_2$).
• Supplying fresh oxygen to the birds.

The required airflow rate (measured in cubic feet per minute, CFM) varies depending on the birds' age and the outside temperature. There are typically two main ventilation calculations:

• Minimum Ventilation: This is used during cold weather to remove moisture and gases without overcooling the house. The calculation is often based on a specific CFM per bird:

  $$\text{Minimum Airflow (CFM)} = \text{Number of Birds} \times \text{CFM per Bird}$$

  For example, a common guideline is $0.1 \text{ CFM/bird}$ for young chicks, increasing to $0.25 \text{ CFM/bird}$ for older birds.

• Maximum Ventilation (Tunnel Ventilation): This is used during hot weather to provide significant cooling by creating high air speeds across the birds. The calculation is based on the cross-sectional area of the house and the desired air speed:

  $$\text{Maximum Airflow (CFM)} = \text{House Width (ft)} \times \text{House Height (ft)} \times \text{Desired Air Speed (ft/min)}$$

  A typical desired air speed for tunnel ventilation is $400 \text{ to } 600 \text{ feet per minute}$.

  Example: For a house $40 \text{ ft}$ wide and $8 \text{ ft}$ high, with a desired air speed of $500 \text{ ft/min}$:

  $$\text{Maximum Airflow (CFM)} = 40 \text{ ft} \times 8 \text{ ft} \times 500 \text{ ft/min} = 160,000 \text{ CFM}$$

The total "force" or capacity of the ventilation system (i.e., the fans) must be sufficient to provide these calculated airflow rates to maintain optimal conditions for the broilers.

The required airflow rate for a poultry broiler house is calculated using the following formulas:

• Minimum Ventilation: $$\boxed{\text{Minimum Airflow (CFM)} = \text{Number of Birds} \times \text{CFM per Bird}}$$
• Maximum Ventilation (Tunnel Ventilation): $$\boxed{\text{Maximum Airflow (CFM)} = \text{House Width (ft)} \times \text{House Height (ft)} \times \text{Desired Air Speed (ft/min)}}$$