Is it a good idea to build my own laminar flow hood?

Answer from a Biosafety Officer:

June 10, 2013

We would not recommend building a laminar flow hood for the use of handling potentially infectious materials.  At Biosafety Level 2 (appropriate for handling agents that can cause disease in healthy adults), procedures that can potentially create infectious aerosols should be performed in biosafety cabinets. While laminar flow hoods are designed to protect the material within the cabinet, biosafety cabinets are more complex and are designed to not only protect materials within the cabinet, but also the individual working with the materials, and the environment.  

For more information see: http://www.labcompare.com/Product-Focus/6-Laminar-Flow-Hoods-and-Biological-Safety-Cabinets/ and http://www.cdc.gov/biosafety/publications/bmbl5/BMBL5_appendixA.pdf.