This is one typical example of what a pitch pocket is. Now, since you mentioned that the foam insulation was intact on the pipe that penetrates through the roof surface verically, I would also ask that you check the brittleness of the foam wrap around insulation to see several things.
Is the foam brittle and deteriorating?
Is there any gaps or seams where in intersects the roof?
Even if someone slopped plastic roof cement around the circumferance of the insulation around the pipe, the roofing cement by itself will expand and contract until it becomes too brittle itself and loses its pliability. When that occurrs, the penetrating hole can only become more brittle and prone to additional cracking, even if very minor at first.
A slow and saturating rain will more likely find this roofing defect rather than an instantaneous deluge of a significant volume of water. The large volume of water from a 2 1/2 gallon bucket will too quickly disperse from the area in question. A better test would be a running garden hose pointed at this area if it is not trecherous and freezing on the roof surface or even better, a very close detailed eyeball view of the area penetrated.
If the tube actually goes through some sort of a pitch pan, aka, a pitch pocket, then check the sealant that fills up the interior of the metal flashing. You would be looking for cracks and a level lower than the perimeter edges of the sheet metal pitch pocket flashing.
Also, if the insulation is in direct contact with the pitch pocket filler, (usually just plain old roofing cement), then take a stanley box cutter knife and cut away several inches of the insulation where it is penetrating the filler compound.
At this point, but some very good polyurethane caulk, such as Vulkem Sealant and fill in the gaps and build up the pitch pocket filler with this sealant to form the appearance of an ice cream scoop on top of a cone. This will allow for the water to slide off of the material to the exterior of the pitch pocket and not settle in the center until it finds the minor cracks, which is akin to having a drain opened up in a sink.
Also, make sure thet you coat the noewly exposed portion of the pipe tubing that runs through which you have recently exposed by cutting away the insulation. This will cover up the future affects of not having that portion of the piping being uninsulated adequately enough.
Ed
Pitch Pockets
[/URL]
Pitch Pocket
Pitch Pockets are flanged, open-bottomed, metal containers, placed around columns or other roof penetrations. They are filled with hot bitumen or flashing cement in order to seal the joint, thus blocking penetrations of the roof. Pitch pockets are easy to install. You can simply open it up and wrap it around the roof penetration. All that is required is some light hammering to the corner lock in order to hold it together. This quick installation provides a water tight seal. B&B Pitch Pockets are available with or without soldered corners.