Secondary containment requirements are addressed by the Environmental Protection Agency (EPA) through the Resource Conservation and Recovery Act (RCRA) contained in title 40 of the Code of Federal Regulations (CFR) part 264, the 2006 Uniform Fire Code (UFC) in standard 60.3.2.8.3 and in the 2012 International Fire Code (IFC) in 5004.2.
You should check your visa endorsement for the period of your stay in Zambia. Although you are allowed 90 days per calendar year the immigration officer will not normally endorse the full length of time upon entry and you will be required to extend the stay at the nearest immigration office.
But you probably have to apply for extensions. (Countries where you can stay 180 days visa free or on a tourist visa?) As for Tourist visas are typically good for between 30 and 90 days., it is not true. There is a difference between validity of tourist visa (for how long is it valid?) and maximum duration of stay.