SRDs and Cell Phones

1
Take 5 for Safety

• SRDs and Cell Phones
• New Equipment Causes Damage
• Failure of Secondary Electrical Barrier
• Collider-Accelerator Department
• 10-14-2008

2
EMI from Cell Phones - Warning

• Electromagnetic interference (EMI) was observed
  between cell phones and SRDs
• Distances greater than about 30 cm are sufficient
  to achieve EMI suppression
• The EMI can be prevented by enclosing the SRD in
  a conductive shield
• e.g., anti-static bag typically used for computer
  parts
• Shielding should be incorporated into design of
  SRDs by manufacturer
• Many detailed studies have been published on the
  EMI between cell phones and various medical
  devices
• The internationally-recognized standard IEC
  60601-1-22001 specifies that non life-supporting
  medical electrical equipment and/or medical
  electrical systems must be subjected to a
  radiated field RF at an immunity test level of 3
  V m-1 over the frequency range 80 MHz to 2.5 GHz
• For life-supporting equipment, the specified
  immunity level is 10 V m-1
• This limit can be exceeded by some cell phones
  operating at full power even at distances of more
  than 1 m away
• Reference Physics in Medicine and Biology, 50,
  N93-N99 (2005)

3
Critique 6 for FY08 New Equipment Causes Damage

• Engineer and technician tested a quench
  protection assembly (QPA)
• Test equipment was first time use (i.e., new
  current signal generator)
• Assumed prior experience with similar test
  equipment was sufficient
• Assumed first measurements were indicative of how
  test equipment would always behave
• During adjustments on new test equipment, QPA was
  unknowingly overloaded with current pulses
• Corrective Action
• Human Performance Committee
• to help Electrical Groups develop
• standard practice for
• using new test equipment

4
Critique 7 for FY08 Failure of Secondary
Electrical Safety Barrier

• Tech entered North Gate at AGS with his key after
  gate locks were electrically disabled by MCR
• Equipment covers in place gate was secondary
  safety barrier
• Gate found not to latch when shut every time
• Gate fixed
• Corrective Actions
• Check gate during sweep to ensure it latches when
  closed
• Investigate the use of an audible/visual alarm at
  MCR if gate opens and/or warning to entrant
• Add warning sign and tape barrier to gates
• Add this information in training

5
Ladders With Wheels