C. RISK ASSESSMENT FOR WORKING WITH X …

1 Document: Risk ASSESSMENT for WORKING with X-rays in room , Flowers building Created by Liz Carpenter Last revised on 31st of March, 2003 - 1 - C. RISK ASSESSMENT FOR WORKING with X-RAYS IN THE X-RAY CRYSTALLOGRAPHY SUITE, ROOM , FLOWERS BUILDING DEPARTMENT: Center for Structural Biology, Flowers Building, Biological Sciences. ROOM/LAB: SUPERVISOR: Paul Freemont MANAGER: Liz Carpenter 1. Activity: This document covers the risks associated with WORKING with X-rays in the X-ray crystallography facility, room , Flowers Building, Imperial College. 2. The X-ray facility The X-ray facility consists of three X-ray generators from Rigaku-MSC, three X-stream crystal freezing sets and three image plates from MAR.

2 The equipment is housed in three separate experimental areas (hutches) within room The X-ray shutters are interlocked, so that when the users are WORKING near the X-ray equipment, the X-ray shutters are closed and no X-rays are emitted from the system. Only by closing the lead impregnated plastic doors and activating the interlock switches can the shutters be opened to allow X-ray emission in the experimental area. The system is designed to prevent anyone exposing themselves to X-rays. 3. Properties of X-rays and hazards associated with use of X-rays in the facility: X-rays are electro-magnetic waves We use copper k-alpha radiation of wavelength . We use a single well-collimated beam of approximately 200 um x 200 um. If these X-rays hit a part of the body they would be absorbed by the first few millimeters of the body This causes burns in the short term There is a risk of cancer in the long term These X-rays can be detected using a Geiger counter.

3 4. Risk ASSESSMENT and control measures in place: The table below shows the risks to anyone who may be involved in the use of X-rays in room and those who may have access to the facility. Document: Risk ASSESSMENT for WORKING with X-rays in room , Flowers building Created by Liz Carpenter Last revised on 31st of March, 2003 - 2 - The risks to the general public are minimized by preventing access to the laboratories where the work is carried out. Swipe cards are required for access to both the building and the X-ray laboratory. Activity: Mounting crystals, testing crystals and collecting data using the X-ray generators in room This facility is used for collecting X-ray diffraction data from crystals of macromolecules.

4 Generally these crystals are kept at 100 kelvin with an X-stream cooling system. Crystals are mounted on the X-ray camera in fibre loops in a stream of N2 gas at 100 K. Alternatively crystals are mounted in glass or quartz capillaries and data is collected at room temperature. Users leave the experimental area, close the doors and activate the interlock system before the crystals can be exposed to X-rays. Risk: exposure to X-rays leading to burns and possible carcinogenic effects. Risk to: Control measures: Direct users Summary The risk of exposure to X-rays are minimized by preventing anyone from having access to the X-ray equipment when all the shutters are open. No-one should ever be in the experimental area when X-rays are being emitted.

5 The equipment All this equipment is new: the oldest system is 3 years old, the other systems are less than 2 years old. All equipment is housed inside an interlocked experimental area (hutch). X-rays can not penetrate the glass doors or the brick walls between the hutches. The X-ray beam is directed away from the area where the users sit when data is being collected. The generators have a number of safety features: The generation of X-rays is disabled when the visual indicator lights are not WORKING . The shutters are disabled with the shutter open warning lamps are not WORKING . X-ray production is disabled if a shutter fault occurs (sticks open or is forced open). The main circuit breaker is disabled, removing all power to the generator, if any access panels are removed.

6 There is an emergency panic button on the front of the generators which turns the generator off. Document: Risk ASSESSMENT for WORKING with X-rays in room , Flowers building Created by Liz Carpenter Last revised on 31st of March, 2003 - 3 - Interlocks: When users are WORKING with crystals near the X-ray generator there are always two shutters closed on the generators. In order to obtain an X-ray beam the users must leave the experimental area, close the glass doors, activate the hutch interlock by pressing a button and turning a key or flicking a switch. The interlock will not work unless the door is properly closed. The final shutter is opened from the computer screen outside the hutch. If the door to the hutch is opened at any time when the shutters are open, the shutter will close automatically.

7 Interlock override There are override keys for the interlock. These are kept is in the possession of the X-ray technician and the facility manager. They are not left in room This allows the interlock system to be inactivated when maintenance work requires the X-ray technician to work in the hutch with the beam on. Only the trained technician, Ian Coole, can perform this task, no user has access to the key. Training All users will be trained in the use of the X-ray equipment either by their supervisors or by the X-ray laboratory facility manager, Liz Carpenter. The users are also required to read the local WORKING rules and the facility risk ASSESSMENT . All users are required to complete the Registration form for Users of the X-ray Crystallography Facility.

8 This consists of two parts, the college registration form WORKING with ionizing radiation - new users registration form and Training record for users of the X-ray facility, room , Flowers Building . Prior to becoming a registered user all users must complete these records to indicate that they have read the local rules and risk ASSESSMENT . They must also sign that they have received training in the use of the facility and obtain a signature from their trainer. User tests for X-ray leaks A Geiger counter is available in the X-ray laboratory and users are trained in its use. They are required to scan the area around the crystal mounting position prior to starting work and when they finish. The maximum reading is to be recorded at the start of each experiment.

9 Should any part of the generator, collimator or shielding be dislodged or knocked during an experiment the users are told to stop work immediately and see either Liz Carpenter or Ian Coole to discuss any possible problems with the equipment. Signs to provide suitable information There are signs on the door of the X-ray facility indicating that it is a restricted area where X-rays are produced. Document: Risk ASSESSMENT for WORKING with X-rays in room , Flowers building Created by Liz Carpenter Last revised on 31st of March, 2003 - 4 - Safety check by the manufacturers: All three generators were subject to a safety ASSESSMENT by the manufacturers, Rigaku MSC, on the 29th of August, 2002. All three were certified as safe by the company on that date.

10 We have arranged a yearly maintenance contract which includes a yearly visit to our site in which we include a safety check of the equipment by the manufacturer to ensure that no problems have arisen in a given year. These safety checks will be performed each year. Safety check by college safety department: The Safety department radiation officer, Mark Ramsey will be carrying out unannounced safety checks of the facility at intervals. Maintenance: General maintenance of the X-ray equipment is performed by our specialist X-ray technician, Ian Coole. We will have regular maintenance visits from Rigaku MSC to ensure that the equipment is properly checked. We have a service contact arranged from March 2003 to March, 2004.