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Below is an email from one of our major project teams who are building some tunnels as we speak.  They are having an issue with the stand pipes.  Do you have any suggestions?

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As discussed last week, the Mitchell Interchange Construction team is looking at options to enhance standpipe protection within Tunnel construction at the request of the City of Milwaukee Fire Department. MFD is requesting  "the maximum, reasonable,  protection and/or isolation of the standpipe outlets from vehicular damage".    Currently the standpipe system has been protected with 7"  (+/-) lateral offset to connection fittings in Tunnel 3.  Tunnel 1 and 2 will have nearer to 10" of lateral offset to standpipe that is located about 18" above the top of barrier.  Our construction team has dismissed the potential to change to vertical face barrier due to potential increased damage to vehicles involved in a crash.

Construction team has identified that we have met NFPA requirements:

9.3.3 " Fire department connections shall be protected from vehicular damage by means of bollards or other approved barriers.

9.4.3 " Hose connections shall be located so that they are conspicuous and convenient but still reasonably protected from damage by errant vehicles or vandals

Team has discussed locating bollard, or some physical protection on top of the barrier at the same offset as the standpipe fittings.  You offered some hesitation with that alternative in our phone call last week, and also potential to look at other alternatives.  Can you look into, and get me an assessment on physical protection alternatives " bollard and other?

I am unaware of any special protection barrier systems that have been designed and tested for use in shielding water values which extend off of the tunnel side walls and above the vehicular barriers. However, if safety treatment is desired, it would seem possible to design steel or reinforced concrete structures which anchor to the top of the concrete parapet and possibly to tunnel wall in order to prevent vehicle snag, and even occupant snag, on the pipe hardware.

If this barrier option is considered, then the upstream and downstream ends should be sloped to mitigate snag concerns as the additional protective barrier which falls within the zone of intrusion. As noted above, these systems could be attached to barrier or tunnel.

Alternatively, it may be reasonable to consider design changes to the pipe system, such as to recess more the structure (i.e., 2 outlets and handle for valve) within the tunnel side walls, thus greatly reducing concerns for vehicle snag, and even occupant snag, on the pipe structure.