Introduction

In a laboratory, it is not only a question of comfort but also of the safety of people. During experiments and research, a variety of harmful substances and fume may be released into the air which may have a negative effect on the health of staff and students. Therefore, it is important to install a good ventilation system to ensure fresh and clean air in the laboratory.

In this article we will look at how to make and install a laboratory ventilation system ourselves. We will describe the necessary steps from planning and design through to installation and configuration of the system. We will also discuss the importance of safety precautions and fire regulations in the installation and operation of the ventilation system.

We hope that this article will help you create a safe working environment in your laboratory and make the hood installation process more understandable and accessible to anyone wishing to tackle the task themselves.

How to Make a Fume Hood Part 4 – Ducting and Testing

Ventilation Requirements

Before proceeding with the design and construction of a fume ventilation system for a laboratory, it is necessary to determine the requirements for the fume ventilation system. The basic requirements for a laboratory ventilation system include:

• 1. Performance. The volume of air to be pumped from the laboratory per unit of time must be determined. This will depend on the quantity and nature of substances and equipment used in the laboratory.
• 2. The type of ventilation system. There are various types of exhaust systems: exhaust system, forced-air exhaust, forced-air and exhaust system. Each type is suitable for specific conditions.
• 3. Place of installation. The exhaust system must be installed in the most suitable location for the laboratory equipment and for the comfort of the staff.
• 4. Noise level. It must be considered, that the suction system can generate noise that may negatively influence the work in the laboratory. Therefore, it is advisable to choose a hood with a minimum noise level.
• 5. Safety. The suction system must ensure the safety of staff and prevent the possibility of explosion or fire if explosive substances are used in the laboratory.
• 6. Conform with local regulations and safety requirements. Local regulations and requirements for fire and safety of work in the laboratory must be considered.

With these requirements in mind, the optimal laboratory ventilation system can be designed.

Calculation of Required Suction Performance

The calculation of the required laboratory ventilation performance depends on several factors, including the size of the laboratory, the amount and nature of substances and equipment used and the environmental impact.

The following parameters should be considered for the calculation of the suction capacity:

• 1. Volume of the laboratory. The calculation of fume suction capacity starts with the volume of the laboratory to be ducted. The laboratory volume is measured in cubic meters.
• 2. Quantity of equipment. The amount of equipment to be used in the laboratory must be considered. Different types of equipment may produce different harmful substances that will need to be drawn from the laboratory.
• 3. The nature of the substances used. The nature of the substances used must be considered, including their viscosity, density, evaporation rate, etc. This makes it possible to determine the velocity of the substances in the air, which in turn affects the required suction capacity.
• 4. Standards and requirements. The calculation of the suction capacity must also consider local regulations and requirements for fire and safety work in the laboratory.

Based on these parameters, the required suction capacity of the suction system can be determined. Normally, the suction capacity is defined in cubic meters of air per hour. Typically, laboratories use systems with an air exchange rate of 10 to 20 air volumes per hour.

For instance, if a laboratory has a capacity of 100 cubic meters, and 10 air volumes per hour are required, the required suction capacity will be 1000 cubic meters of air per hour.

Choosing of Ventilation

There are many factors to consider when choosing the type of hood for a laboratory, including the nature of work in the laboratory, the volume of the room, the amount and nature of substances and equipment used, and the budget.

There are several types of suction systems that can be used in laboratories. Let us look at some of them:

• 1. The supply and exhaust system. This is the simplest and most affordable type of suction system that allows a constant circulation of fresh air in the laboratory. A supply and exhaust system consists of two parts: a fan that pumps contaminated air and a ventilation unit that supplies fresh air to the laboratory. However, this type of system is not designed to remove hazardous substances and may not be suitable for laboratories with high safety requirements.
• 2. Recirculation exhaust system. This type of system is used for laboratories that handle small quantities of hazardous substances. It allows contaminated air to be pumped and cleaned, then returned to the laboratory. But this system is not suitable for laboratories with high safety requirements and is not capable of handling large volumes of air.
• 3. Suction system with exhaust to the outside. This is the most efficient type of suction system and is suitable for laboratories with high safety requirements. It allows contaminated air to be pumped and discharged outside the laboratory. This is accomplished using a fan, which pumps air through an exhaust duct and discharges it outside the building. This type of system is the most expensive but provides the most effective protection for those working in the laboratory.

Materials for Fume Suction

The most common materials used in the construction of suction systems are:

• 1. Stainless steel. It is a material that is strong and resistant to corrosion, making it ideal for use in laboratory environments where hazardous substances may be in contact with the ventilation system.
• 2. Plastic. Plastic materials can be used in laboratories where low levels of hazardous substances are present. They are lightweight, strong and corrosion resistant.
• 3. Aluminum. Aluminum materials are strong but have little resistance to corrosion. They can be used in laboratories with low levels of harmful substances.
• 4. Glass fiber. The fiberglass material is strong and corrosion resistant. It can be used in laboratories with low levels of harmful substances.
• 5. Ceramics. Ceramic materials have high resistance to corrosion and high temperature. They can be used in laboratories where the air may be contaminated by acids or alkalis.

Tools for Making the Ventilation System

You will need the following tools and equipment to make a hood for your laboratory:

• 1. Pliers and needle-nose pliers
• 2. Ruler and tape measure
• 3. Screwdrivers and spanners
• 4. Rotary hammer and drill/drill set
• 5. Carpentry knife and saw
• 6. Scoring tool and spirit level
• 7. Marker and pencil
• 8. Ladder or stepladder
• 9. Pipe clamps and fittings
• 10. Foam and sealant

Installation of the Ventilation System

Basic steps for installation of a ventilation system in a laboratory:

• 1. Preparing the ventilation installation place. Determine the exact position of the hood and clear it from any unnecessary objects. If necessary, fixing elements must be installed.
• 2. Fan installation. The fan must be installed in accordance with the design and connected to the duct system. If necessary, sound-absorbing materials are to be installed to reduce noise.
• 3. Installation of ducts. The ducts are to be installed according to the design, using the fixing elements. Connect the ducts to the ventilation grilles and install them in place.
• 4. Installation of control dampers. You have to install the control dampers in the ducts, according to the design.
• 5. The connection to the power supply. It is necessary to connect the fan to the power supply and make sure that it works properly.

Maintenance and Cleaning of the Ventilation

The following are general guidelines for the maintenance and cleaning of the ventilation in a laboratory.

• 1. Regularly check the condition of the filters. The filters in the ventilation must be cleaned or replaced at regular intervals, depending on the degree of contamination of the laboratory air. Normally the filters should be cleaned or replaced every 6-12 months.
• 2. Clean the ventilation grilles. Ventilation grilles must be cleaned regularly to prevent dust and dirt from clogging and interfering with the free flow of air. Cleaning can be done with a damp cloth or a brush.
• 3. Check the operation of the fans. The fans should run smoothly, if they start to produce noise or work unevenly, they should be checked and replaced if necessary.
• 4. Check the condition of the exhaust pipe. The exhaust pipe must be free of obstructions such as dust, dirt, leaves and other materials that may obstruct the free flow of air. Also check it for cracks because they can cause air leakage.

Conclusion

In conclusion, it can be said that it is possible to make a laboratory ventilation yourself but requires some knowledge and skills in ventilation and design. It is important to consider performance requirements and choose the right type of fume hood, as well as the right materials and tools.

A properly installed and maintained ventilation is a key factor in ensuring a safe and comfortable work environment in the laboratory.

By following the guidelines outlined in this article, you can build and install your own laboratory ventilation, which will help to ensure a safe and comfortable laboratory environment.

Bibliography

• Assessing general ventilation effectiveness in the laboratory Ralph Stuart, Ellen Sweet, and Aaron Batchelder J. Chem. Health Saf. 2015, 22, 2, 2–7 Publication Date: March 1, 2015 © 2014 American Chemical Society https://doi.org/10.1016/j.jchas.2014.10.001
• Experimental study of ventilation performance in laboratories with chemical spills Mingang Jin, Farhad Memarzadeh, Kisup Lee, Qingyan Chen Building and Environment Volume 57, November 2012, Pages 327-335 https://www.sciencedirect.com/science/article/abs/pii/S036013231200159X
• Proposed Procedure to Design an Optimum Ventilation System for Chemical Laboratory Gara Idrees Abdoon, Nagwa Fadl Bashir Department of Chemical Engineering, Faculty of Engineering, ALNeelain University, Khartoum, Sudan.
• https://www.scirp.org/journal/paperinformation.aspx?paperid=77830
• Laboratory air quality and room ventilation rates Robert C. Klein, Cathleen King, and Anthony Kosior Cite this: J. Chem. Health Saf. 2009, 16, 5, 36–42 Publication Date:September 1, 2009 © 2009 American Chemical Society
• https://doi.org/10.1016/j.jchas.2008.12.004
• Room Ventilation and Its Influence on the Performance of Fume Cupboards:  A Parametric Numerical Study Jordan A. Denev, Franz Durst, and Bernhard Mohr Cite this: Ind. Eng. Chem. Res. 1997, 36, 2, 458–466 Publication Date: February 3, 1997 © 1997 American Chemical Society https://doi.org/10.1021/ie960218n