Thanks for posting.
The CDC and ISSI links contradict what the Nolvasan letter says. The beautifuldragons link is very pretty but it doesn't list the sources of the information.
From CDC:
Contact Times for Surface Disinfectants
An important issue concerning use of disinfectants for noncritical surfaces in health-care settings is that the contact time specified on the label of the product is often too long to be practically followed. The labels of most products registered by EPA for use against HBV, HIV, or M. tuberculosis specify a contact time of 10 minutes. Such a long contact time is not practical for disinfection of environmental surfaces in a health-care setting because most health-care facilities apply a disinfectant and allow it to dry (~1 minute). Multiple scientific papers have demonstrated significant microbial reduction with contact times of 30 to 60 seconds. In addition, EPA will approve a shortened contact time for any product for which the manufacturers will submit confirmatory efficacy data.
From ISSI:
The conclusion of the investigation shpwed that 0.25% concentration of chlorhexidine and 90" [seconds] contact time were the most effective concentration and contact time for inhibition methicillin resistant staphylococcus aureus growth.
From F10:
Bactericidal test standard contact times are generally 5 minutes. However it was found that a log3 reduction in gram positive bacteria was achieved in 30 seconds and similarly 60 seconds for gram negative bacteria all at a concentration of 1:500 of the F10SC Veterinary Disinfectant.