Is there a limit in /tmp folder size?

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Hi

As part of our project we will be developing PHP script to extract attachments from Incidents and place in /tmp folder to be picked by Cron Script to move to a network folder.

1) I would like to know, if there is any size limit for /tmp folder? If so what is the limit?
2) Will there be any impact to application functionality or performance based on the files being present in /tmp folder?
3) Is there a way to access the /tmp folder using any FTP tool or through tools similar to accessing WebDAV?
4) Is there any other folder or space within our instance apart from /tmp, where we can place extracted files temporarily (24 Hours to 48 Hours)?