Even though you setup a static IP on your Pi you will still need to forward the default port 22 to the Pi, on your Router.
After you have forwarded it you will then need to know the IP of your home internet connection. Most of the time they are dynamic and change as defined by the ISP. You can overcome this by setting up dynamic dns on the Pi.
My favuoritre free DynDNS provider is no-ip but any one will work the same. Install the client to update your IP to the DNS record.
sudo apt-get install ddclient
Then go and edit the configuration file .
# Configuration file for ddclient generated by debconf
daemon=60 # check every 60 seconds
syslog=yes # log update msgs to syslog
mail=root # mail all msgs to root
mail-failure=root # mail failed update msgs to root
pid=/var/run/ddclient.pid # record PID in file.
ssl=yes # use ssl-support.
use=web, web=dynupdate.no-ip.com # get ip from server.
server=pi.no-ip.org # Your DNS
login= # your login
password= # your password
Then at work or anywhere else in the world you can connect to your Pi over ssh using the DNS you have selected.
sudo ssh pi@[mypi.no-ip.org]