The DIRC tunnel at BaBar is a Permit Required Confined Space (PRCS).
All confined spaces pose a risk of bumps, scrapes, and lacerations. PRCSs,
however, have the potential for hazardous atmospheres (such as oxygen
deficiency) and additional physical hazards (exposed electrical hazards or
moving parts). For these reasons access to the DIRC tunnel is blocked by a
barrier that can only be removed for authorized access. All accesses require a
permit to be filled out by the PRCS supervisor
and proper work authorization. Authorization during down times (when the barrel
plug is out) can be obtained during the morning or afternoon safety meetings. During
the running cycle can be authorized by the run coordinator.
Access to the DIRC tunnel requires opening the backward
doors and removal of the plug.
(Note: Permit records are kept at IR2 for
current year with copies sent to BaBar Administrators Office at the end
of the year)
The Vesda smoke detection system used on BaBar is
highly sensitive and may go to alert or alarm when certain types of work are
done on the detector or even in/or near the hall. Therefore any smoke or dust
producing work to be done in/or near IR2 (bldg. 620) must be reviewed and
approved prior to the work commencing.
The impairment of the Vesda does not leave the detector without fire protection;
only to lower the sensitivity of the system. It must be remembered
that if a great deal of smoke is generated the system will still alarm.
Impairment is done by the SLAC fire techs and usually follows a standard day
shift. The system is returned to full function before the day shift ends. This
is done around 2:30 p.m. If the smoke detection needs to be impaired into the swing shift, special arrangements have to be made well in advance.
Complete the BaBar Vesda Impairment Form (pdf)
Contact CEF Department help desk at 8901 to
schedule the impairment.
State your name and location and which Vesda zone
you need to have impaired, the reason and the duration of the
After a reasonable amount of time (half hour)
confirm that the impairment has taken place and that it is the proper
zone. If it is, work may now proceed. Remember the smoke detectors will
come on at 2:30 p.m. so plan work accordingly