Stoping small oil and smoke leak? How to make it NFPA 85 acceptable?

[USAeng]

On a burner front in a boiler we have oil igniters we're installing that seem to have a problem with a little smoke mixed with fuel oil coming back out of a guide tube into the area where men will be working sometimes... it is coming out between the OD of the oil gun and the id of the guide tube... we tried making a little seal on the end using a collar, but its definately not a good enough seal and the mist just finds its way around it.... obviously this is not ok... so I was thinking about installing a cam and groove clamp like this:

http://www.mcmaster.com/#catalog/116/296/=8yoagt

would this be ok to nfpa code? It will stop all flow from coming out into the area for sure... any other ideas? there is not a ton of smoke/fuel... just enough to make us want to try and stop the leak... thanks for any suggestions!