Is there a way to download and run an IRC client without administrator privileges?

If your computer is properly configured from a security standpoint, you may be able to download the installation file but not run it. The installation of the IRC client will require administrator privileges because it changes computer settings and opens ports for communications. Because IRC connections are usually unencrypted and typically span long time periods, they are an attractive target for hackers. Because of this, careful security policy is necessary to ensure that an IRC network is not susceptible to an attack such as an IRC takeover war. IRC can also be used for file sharing, so secure networks will block most or all IRC traffic to prevent exfiltration of sensitive information - which is another reason they should prevent non-administrators from installing IRC clients on their machines. Even if you already have an IRC client on your computer, if you connect it to a network that enforces blocking of IRC traffic you still will not be able to communicate via IRC over that network.