CERN/ST-MA/FB
4-12-2003
User Requirements for Fire Detection in LHC-b
Distribution:
1.
D. Lacarrere EST-LEA
Introduction
The UX85 cavern will be split into 2 separate caverns called Zone A and Zone B. Zone A
will be a protected zone (no radiations) whereas Zone B will be subject to ionisation radiation.
Fire detection will have to be installed in the two caverns for both the protection of people
(TIS requirement) and the protection of material (LHC-b requirement).
A fire detection control panel dedicated to LHC-b will be installed against the left wall of
the lift shaft (RB 84 side) in the UX85 cavern. It will be connected to a remote control
keyboard installed in SY8. This will enable the fire brigade to have an easy and fast overview
of an eventual fire problem that may occur in the cavern.
All the LHC-b fire detectors will be connected to this control panel.
The control panel, the remote control keyboard as well as their installation will be paid by
ST/MA.
2.
Fire detection proposals
2.1.
Zone A
2.1.1. Infrastructure
Air sampling fire detectors will be used in order to obtain the most efficient and reliable
fire detection.
Air sampling tube 1:
This is an existing tube (Delphi leftover). It is fixed under the foot bridge that is installed
under the roof of the cavern.
An air extraction duct is actually positioned on the foot bridge. ST/CV will adapt it to
serve as an air extraction duct for Zone A.
In order to profit from the air movements created by the air extraction, the existing fire
detection air sampling tube will be positioned underneath this duct on the air inlets. The
length of this tube is of 30m.
Air sampling system 2 & 3:
These tubes will be installed on the extremities of the crane’s path (one on each side of the
cavern).
The length of these tubes will be around 40m each and they will be connected to one
common detector that will be fixed near detector 1 (described above).
F. Bonthond
2
Type of detectors to be used with these tubes:
The height at which the tubes will be installed will make the detection of smoke very
difficult. When going up, the smoke cools of and with the ventilation mixing the air in the
cavern, the level of dilution will be significant. In order to obtain a satisfactory smoke
detection, the use of very sensitive detectors is strongly recommended.
Installation
It will be difficult to install pipes 2 and 3 on the extremities of the crane’s path. LHC-b
agrees to set up scaffolding equipment.
2.1.2. Barracks
Leftover from Delphi, there are 16 air sampling tubes still installed in the barracks. They
seem to still be in excellent state so they will be reused with only minor adaptations.
The existing tubes are listed hereafter:

Barrack D1 on the ground floor:
- 1 tube fixed on the ceiling
- 2 tubes fixed on the 2 air conditioning units
- 2 tubes fixed in the false floors

Barrack D2 on the first floor:
- 1 tube fixed on the ceiling
- 2 tubes fixed on the 2 air conditioning units
- 2 tubes fixed in the false floors

Barrack A2 on the second floor:
- 1 tube fixed on the ceiling
- 1 tube fixed on the air conditioning unit
- 1 tube fixed in the false floors

Barrack B3 on the second floor:
- 1 tube fixed on the ceiling
- 1 tube fixed on the air conditioning unit
- 1 tube fixed in the false floors
Once all the equipment will be installed inside, we will be able to determine if additional
fire detectors are required or not.
LHC-b will investigate the need for Break-the-glass buttons inside the barracks for
manual activation of a fire alarm. If so, the locations for these buttons should be defined.
2.1.3. Around PZ84 shaft
Fire detection is required by LHC-b on the ground, first, second and third floors.
Low air disturbances are expected in these areas.
Identification per level is required.
4 air sampling detectors will thus be installed. The tubes will be positioned above the
expected risks (racks, UPS, …).
3
2.2.
Zone B
2.2.1. Infrastructure
The fire detection that will be installed in this zone for the infrastructure protection will be
similar to that of Zone A.
All the detectors will be installed in Zone A.
Air sampling tube 1:
For details, see tube 1 in Zone A.
The length of this tube is of 45m.
Air sampling tubes 2 & 3:
These tubes will be installed on the extremities of the crane’s path (one on each side of the
cavern).
The length of these tubes will be around 55m each and they will be connected to one
common detector that will be fixed in the middle of the separation wall.
Type of detectors to be used:
The same constraints and questions as for Zone A apply to Zone B.
Installation:
It will be difficult to install pipes 2 and 3 on the extremities of the crane’s path. LHC-b
agrees to let us use its crane.
2.2.2. Platforms (against US85 wall)
This is the cryogenics zone. S. Claudet will determine the need for specific fire detection in
this zone.
3.
Financial estimate
The price for the fire detection for UX85 will be between 50 and 80 kCHF.
4.
Planning
All the fire detection systems will be installed in 2004.