guidelines for laboratory design (health, safety, and environmental considerations) || imaging and...

327

25

25.1 INTRODUCTION

For many years, the photographic process was the only way to capture visual information needed for documen-tation and use. Darkrooms were common in laboratory buildings. Today with the advent of digital imaging many more venues for capturing visual information are avail-able. In addition, there are many processes such as com-puted tomography (CT), ultrasound, positron emission tomography (PET), and magnetic resonance imaging (MRI) used for human, animal, and other object diag-nostics that are used for research purposes. It is antici-pated that new and novel methods will be available to the researchers in the future. The intent of this chapter is to provide information on the design of darkrooms as traditional photography is still used, as well as informa-tion on the design of digital imaging rooms as digital imaging has become more widely used. However, many enthusiasts of black and white images prefer photo-graphs over a digital image. Many forensic laboratories still have darkrooms as many courts still do not allow digital images as evidence.

25.1.1 Digital Imaging Facilities

Digital imaging provides a more fl exible format for how an image can be captured and stored. It eliminates all the need for chemical processing of fi lm. Most of today ’ s diagnostic imaging techniques are only available digi-

tally. Several human and animal tests for clinical research purposes are only possible by digital imaging.

Some of the more common digital imaging processes used are described below.

25.1.1.1 Computed Tomography. CT is used by researchers to obtain detailed visual information on humans in clinical studies, on animals, and on objects such as in fracture analysis in rocks and internal and external examination of critical machine parts. This process uses x-rays; the application, however, is much more sophisticated than traditional body x-rays.

The CT scanner sends x-ray pulses through the subject or the test object. Each pulse lasts less than a second and takes a picture of a thin slice of the object, organ, or area being studied. Each successive pulse takes information on another slice so a computer can generate a composite image. The subject or object rests on a sliding carrier that moves it into the bore of the instrument, as shown in Figure 25-1 .

25.1.1.2 Ultrasound. Ultrasound uses refl ected sound waves to produce an image inside the test subjects or animal body objects or organs.

For ultrasound testing, a gel or oil is applied to the object ’ s surface or subject ’ s skin to help transmit the sound waves. A small handheld instrument (a trans-ducer) is moved back and forth over the area being examined. The transducer emits high-pitched sound

IMAGING AND PHOTOGRAPHIC AND FACILITIES

Guidelines for Laboratory Design: Health, Safety, and Environmental Considerations, Fourth Edition. Louis J. DiBerardinis, Janet S. Baum, Melvin W. First, Gari T. Gatwood, and Anand K. Seth.© 2013 John Wiley & Sons, Inc. Published 2013 by John Wiley & Sons, Inc.

328 IMAGING AND PHOTOGRAPHIC AND FACILITIES

ent imaging information from that of an x-ray, ultra-sound, or computed tomography (CT) scan. MRI also may show anomalies that cannot be seen with other imaging methods. It has become a valuable research tool. Similar to CT scan, MRI instruments may have a sliding carrier to position the test subject correctly within the bore (see Figures 25-3A and 25-3B ). Other MRI instruments have open bores that allow human subjects to sit—not lie down—and can accommodate larger vertical test subjects or objects.

25.1.1.4 Nuclear Medicine Imaging/ Positron Emis-sion Tomography. Medical research imaging is often limited to viewing anatomical structures of the body.

waves, which are above the range of human hearing. These sound waves refl ect back to the transducer. A computer analysis of the refl ected sound waves results in an image that is displayed on a screen. The image produced by this process is called a sonogram, echo-gram, or an ultrasound scan. A permanent record can be made in hard copy, or as a digital fi le or video. A typical system is shown in Figure 25-2 .

25.1.1.3 Magnetic Resonance Imaging. MRI uses a combination of magnetic fi eld and pulses of radio wave energy to make images of organs and soft tissues and structures in the body. MRI in general provides differ-

FIGURE 25-1. CT scanner.

FIGURE 25-2. Ultrasound.

FIGURE 25-3A. Large animal-/human-sized magnetic reso-nance imaging (MRI) scanner.

FIGURE 25-3B. Smaller animal MRI.

INTRODUCTION 329

types. They may be located in the laboratory building or in an ancillary building. Digital imaging has replaced most—but not all—wet-process photographic activities for laboratory-based science.

Darkrooms may be one of the following types:

• A small darkroom for research facilities • Teaching darkrooms for photography and special-

ized art classes • Automated photographic systems used for such

purposes as medical x-ray processing and some kinds of research. (These are getting less used and have been mostly replaced with digital imaging systems.)

Darkrooms have unique design requirements as do some of the digital imaging processes such as MRI and PET.

25.1.3 Work Activities

25.1.3.1 Digital Imaging Rooms. Work activities include the preparation of animals, organs, patients (human subjects), plants, or other items to be investi-gated. For patients or human subject ’ s waiting rooms, changing rooms, lockers, and toilet access is essential.

25.1.3.2 Photographic Darkrooms. Work activities include bulk fi lm handling, mixing of chemicals, devel-oping, washing, rinsing, drying, and printmaking. Photographic processes require carefully controlled environmental conditions, including control of light, temperature, and precise use of chemicals. Film coatings are primarily silver compounds.

25.1.4 Equipment and Materials Used

25.1.4.1 Digital Imaging Rooms. 25.1.4.1.1 MRI . MRI units have strong magnetic fi elds that are continuous. Good shielding to protect personnel and visitors is absolutely necessary. Other unique safety issues must be considered: The website www.MRIsafety.com provides some ongoing valuable information and is an excellent resource.

Most MRI magnets used in patient diagnostic and research are superconducting-type electromagnets. A superconducting MRI magnet has a superconducting wire coil, which has a resistance approximately equal to zero when it is cooled through immersion in cryogenic liquid helium. Once current is fl owing in the coil, it will

Indeed, x-rays, CT, and MRI yield extremely detailed images. It is often useful, however, to acquire images of physiologic function rather than of anatomy. Such images can be acquired by imaging the decay of radio-isotopes bound to molecules with known bio-logical properties. This class of imaging techniques is known as nuclear medicine imaging (see Ollinger, 1997).

The most common form of nuclear medicine scan uses a gamma-ray emitting radioisotope bound to a chemical with known physiological properties. After it is administered, single photons emitted by the decay-ing isotope are detected with a gamma camera. A two-dimensional histogram of the detected events forms a projection image of the distribution of the radioisotope and hence of the chemical compound. An example of such a procedure is a cardiac study using thallium-201. Image intensity is indicative of cardiac perfusion and can be used to diagnose defects in the blood supply; this test is widely used to screen for bypass surgery.

Gamma camera-based planar imaging has three major shortcomings.

1. Images are projection images, so the organ of interest can be obscured by activity in front of or behind the organ of interest.

2. The radiopharmaceuticals used must incorporate relatively heavy isotopes such as thallium-201 and technetium-99m.

3. The lead collimator absorbs many photons, thereby reducing the sensitivity of the camera.

PET has inherent advantages that avoid these short-comings, but the process is costly. The short half-life of most positron-emitting isotopes requires an onsite cyclotron, which is a particle accelerator that requires a trained physicist to operate. The scanners themselves are signifi cantly more sensitive and expensive than single-photon cameras. However, the results can be spectacular. PET not only provides detailed image of the organ being studied, but information on physiologic function status.

25.1.2 Photographic Facility

A photographic facility is designed to provide a variety of services to support research activities such as fi lming, developing, printing, enlarging, and cassette loading. Photographic darkrooms are used for processing black and white and color fi lm and print paper of different


photographic image. Thermostatic controls are usually set to maintain the water and solutions at 75–68°F (24–20°C). Where manual operations are performed with chemicals in open containers, eyewash stations and emergency showers are needed.

Many chemicals used in darkrooms and photographic processes are classifi ed as hazardous. They may include solvents, metals, acids, alkalis, aldehydes, and amines (see Table 25-1 for a partial list). Care should be used to store these chemicals in cabinets designed for hazard-ous chemicals. Some have carcinogenic qualities and must be handled in an exhaust-ventilated area. (More-detailed descriptions of specifi c photograph processes and their associated health hazards can be found in Houk and Hart, 1987; McCann, 2005; Shaw, 1991.)

25.1.4.2.1 Packaged Processing Units. There are basi-cally two types of packaged color-processing photo-graphic systems:

continue to fl ow as long as the coil is kept immersed in liquid helium during the MRI scan.

The shielding on the magnet allows for a smaller fringe fi eld. The fringe fi eld drops signifi cantly as one moves away from the magnet. This shielding is achieved by a second set of superconducting windings, outside of the main coil and with opposite current, which reduces the fringe fi eld. This feature is very important for safety reasons and makes it easier to site the MRI magnet.

In the event of a “quench,” the magnet shuts down; it is unplanned and can be catastrophic. The MRI equipment rapidly heats, raising the system temperature and resulting in the rapid boil-off of the liquid helium. Quench vents on the MRI equipment must be provided and carefully located to ensure proper discharge of gas in this event and prevent harm to humans. Catastrophic release of cryogenic gases can fi ll the laboratory, increas-ing the risk of suffocation or intoxication. In these cases, an emergency, high-rate room ventilation system to remove the asphyxiating or toxic gases fl ashing from the cryogenic liquid may be required.

25.1.4.1.2 Other Digital Imaging Rooms. Many digital imaging systems consist of a specially confi gured station where a patient, research subject, animal, or specimen is placed. Special support equipment is usually located in a separate room. This equipment in general produces a lot of heat; it is frequently better and more economical to provide local cooling than to oversize the central HVAC system. Depending upon the imaging system, some back-up power or uninterrupted power supply may be needed.

Where anesthetics are used on animals, well-designed exhausted locations are required. Many times slot hood stations are provided for this purpose. If animals need to be anesthetized on bench tops, good general exhaust is required.

25.1.4.1.3 Computer Data. A lot of computer informa-tion is generated. It is important that space be provided for necessary data storage and retrieval so valuable data cannot be lost or inappropriately used. Many facilities use an onsite server to store data and have a password-protected data-retrieval system. Cybersecurity may be an important issue.

25.1.4.2 Photographic Darkrooms. Equipment may include optic enlargers, open tanks, enclosed processing equipment (such as automatic processing units, some-times referred to as X-O-Mats, shown in Figure 25-4 ), and dryers. Temperature control of water and chemical solutions is extremely important to the quality of the

FIGURE 25-4. X-O-Mat with silver recovery system.

TABLE 25-1. Typical Chemicals Used in Darkrooms

Silver compoundsZincCadmiumHydroquinoneAcetatesAmmonium hydroxideThiosulfatesTrisodium phosphateHexacynoferratesBenzyl alcohol

PHOTOGRAPHIC AND IMAGING FACILITY LAYOUTS 331

For imaging rooms, it will be necessary to have an anteroom used as a control room because of the radia-tion or magnetic exposure potential near some imaging machines.

The layout sometimes can be vendor specifi c. It is recommended that vendors be engaged early in the design process to confi rm size of the room and establish other utility requirements.

The control room should have direct access to the scanner room and be close to other facilities to ensure a good traffi c pattern.

25.2.1.1 PET Room Layout. All considerations pro-vided in Chapter 13 , Radiation Laboratory should be addressed. Anderson (2007) provides a good discussion of unique aspects of layout.

25.2.1.1.1 Injection Rooms. This is the space where the research subject or patient is injected with the dose. A toilet should be available close to the injection area so that the subject can empty his or her bladder prior to being escorted to the scanner. Privacy curtains, subdued lighting, and noise control should be also be considered.

25.2.1.1.2 Hot Lab. The hot lab has several special requirements. It is the space where doses are calibrated and possibly stored. Shielding requirements can be substantial. The laboratory benches need to be solidly built to withstand the weight of shielded containers of doses. These containers can be large and heavy. For example, one vendor ’ s container is approximately 8 in. × 10 in. × 13 in. (20 cm × 25 cm × 32 cm) and weighs about 66 lbs (30 kg).

25.2.2 Photographic Darkroom Layout

All issues discussed in Section 2 of Chapters 1 and 2 should be reviewed, and if applicable, implemented. Criteria for a good photographic darkroom are the capacity for good ventilation, maintenance of lightproof conditions, and the ability to store chemicals in a safe manner. Figures 25-5 and 25-6 show typical darkroom layouts for small research and large teaching facilities, respectively.

25.2.2.1 Personnel Entry and Egress. In large teach-ing darkrooms, it may be advantageous to divide differ-ent types of work into separate rooms—for example, to put color processing, black and white processing, and

• Kodachrome: Chemicals are an integral part of the fi lm; the processors are very expensive and the quality is uneven.

• Ektachrome: Chemicals are applied to the fi lm; these processors are more widely used.

Packaged processing units are designed for high-volume, assembly-line processing of 35-mm fi lm. They do not require a darkroom facility. Packaged systems are popular because of their compact size and effi cient chemical usage. Most machines can process black and white fi lm, develop negatives and slides, and make prints. Packaged processing systems are either tabletop or fl oor mounted; tabletop models are smaller. They require a supply of tempered water, cold water, and drainage. Many of the package systems contain an elec-tric heater for solution temperature control. The chemi-cals are stored in bottles and dispensed as needed. The spent solution is also stored in containers provided with the unit. Waste containers can either be drained for disposal or stored for silver recovery.

The amount of chemical waste produced in these systems is small. For example, a typical tabletop system that operates all day will generate approximately 2 L of chemical waste. Some of these chemicals are not con-sidered hazardous waste and can therefore go down the drain. Other chemical wastes, including all silver-bearing wastes, are hazardous and must be disposed of accord-ingly. Many large and small darkrooms now consolidate waste fi xer into 10- to 20-gallon drums for later silver recovery (shown in Figure 25-4 ) and hazardous waste disposal cost control. An area for collecting and holding waste chemical liquids, perhaps in their original contain-ers or in drums, as with the fi xer, should be considered in the design phase.

An exhaust outlet should be located near the unit for ventilation. Some machines have exhaust connections; otherwise, a canopy-type capture hood may be suffi -cient. See Chapter 32 , Section 32-10 .

25.2 PHOTOGRAPHIC AND IMAGING FACILITY LAYOUTS

25.2.1 Imaging Room Layouts

Special consideration must be provided for unique con-ditions, i.e., equipment weight, vibration, and shielding requirements; in the case of MRI, the magnetic fi eld must be considered. Radiation shielding considerations are critical in a layout for a PET scanner. In general, a layout consisting of a support equipment room, control room, and a work room where the imaging device is located works well.


FIGURE 25-5. Small teaching darkroom: Sample layout.

Revolving Darkroom Door with Emergency Breakaway Attachments.

X-Ray Film Developer

Light Table

Enlarger

Film Processing Tank

Sink

Print Washer

Emergency EW & SS

Fire Extinguisher

Print Dryer

Alternative Light Locks

KEY

1

2

3

4

5

6

7

8C

8D

9

10

photofi nishing in separate rooms. For rooms of less than 200 net ft 2 (19 m 2 ), one entry/egress is suffi cient. Larger rooms require a second egress. Rooms should be wheel-chair accessible.

Light control is absolutely necessary. As the name suggests, this room type should be capable of achieving total darkness. In small facilities, a special light-tight, multipaneled revolving door is used for entry and egress, but the revolving door must have panels that fold back under moderate pressure to provide unimpeded egress in case of an emergency or when a large piece of equip-

ment must be introduced or removed. Revolving doors are available in l-h fi re-rated assemblies for installation in fi re-rated egress corridor walls. Consideration should be given to providing a swinging door of standard size in addition to a revolving door. It can be used for equip-ment moving and for personnel exit in an emergency. It can also provide access for disabled persons. Figure 25-7 shows an example of a revolving door. In large facilities, a zigzag-type light trap may be used to ensure darkness. This type of entry allows heavier traffi c in and out of the darkroom without having to rely on sealed

PHOTOGRAPHIC AND IMAGING FACILITY LAYOUTS 333

FIGURE 25-6. Large teaching darkroom: Sample layout.

KEY

Primary Access/Egress

Emergency Second Egress

Counter

Classroom/Conference Room

Print Inspection Room

Viewing Booth

Sink with Eye Wash

Emergency EW & SS

Fire Extinguisher

B+W Paper Processor

Enlarger Station

1

2

3

4

5

6

7

8C

8D

9

10

Light Trap

Table

2 Way Rotary Light Lock

Storage Room

Pass-Thru

B+W Film Processor

Film Dryer

Film Processing

Color Film Processing

Film Loading Rooms

Darkroom

11

12

13

14

15

16

17

18

19

20

21

B+W Printing Darkroom

Advanced Student Darkroom

Color Enlarging Darkrooms

Color Print Processor

Finishing Area

Wash

Dryers

Bulletin Board

Manager’s

22

23

24

25

26

27

28

29

30


be wired so they cannot accidentally be switched on. For fl oors subject to spills and splashes, surfaces should be slip resistant, and special mats should be provided with a raised texture or grids at sink work areas to reduce the risk of falls.

25.3 HEATING, VENTILATING, AND AIR-CONDITIONING

25.3.1. Digital Imaging Rooms

HVAC systems for digital imaging rooms pose their own challenges. Some of the requirements for MRI have been already discussed in Section 25.1.4.1 . The support equipment room has most of the heat-producing devices. Local coolers provide an excellent approach to handle this heat load without impacting the overall building supply air system; no special temperature or humidity conditions are required.

Imaging rooms with strong magnetic fi elds require nonferrous duct and piping materials. Imaging rooms with quenching requirements that may release large quantities of helium must be ducted properly. As the discharges are occasional and may never happen, it is critical that the end of the discharge pipe be located to avoid obstruction and be examined periodically.

Most of the imaging equipment has local chillers for process cooling. The chillers are further cooled by the building ’ s central systems as back-up. In more critical applications, a local back-up may need to be provided in addition to a central system back-up.

25.3.2 Darkrooms

Heating, ventilating, and air-conditioning systems for processing darkrooms can be very complex because of the high humidity caused by the use of chemical solutions in open tanks or trays and the wash and rinse processes that add additional humidity to the room. Humidity affects the drying time for negatives and fi lm. When humidity is too low, however, it can cause static electricity that will streak processed fi lm. Relative humidity between 40% and 50% is the recommended range. A temperature range of 68–78°F (20–26°C) is acceptable for most darkrooms. Condi-tions in excess of 80°F (27°C) and 50% RH should be avoided.

Because of the large amount of chemicals used and odors that might be objectionable to others, recir-culation of air from the darkroom is not recommended. The pressure in darkrooms should be negative with respect to all other adjacent rooms. Local exhaust ven-

doorways. A sign or signal light outside the darkroom is used to indicate when developing is in process to ensure that lightproof conditions are maintained.

25.2.2.2 Darkroom Furniture Locations. Sturdy shelves for the storage of chemicals as well as other photographic equipment and supplies are needed. Some photographic supplies may need storage in a lightproof area or cabinet. It is important that suffi cient countertop area be provided for equipment such as enlargers.

Silver recovery systems for the rinse water should be used where volumes are appropriate. Extra space for hazardous waste [5–25 gal (20–100 L) containers] may be needed, when bulking for waste solutions is required (See Chapter 27 , Section 27.1.3.1 for a defi nition of bulking.)

25.2.2.3 Darkroom Surface Finish Considerations. Walls in darkrooms are sometimes painted dark colors to reduce chance refl ections from an unexpected light source. When safe lights (i.e., special fi xtures with a variety of light fi lters that provide minimum illumina-tion so as not to damage or otherwise affect the photo plates) are switched on, normal working lights should

FIGURE 25-7. Darkroom revolving door.

HEATING, VENTILATING, AND AIR-CONDITIONING 335

tilation should be used to control the nuisance level of odorous and irritating chemicals in mixing areas and at sinks.

Some photographic fi lm processing requires dark-rooms with a dust-free environment. For these, use of HEPA fi lters in a laminar fl ow cleanroom confi guration or laminar fl ow workstations should be considered. Usually, 85% effi ciency bag-type disposable fi lters will be adequate (ASHRAE, 2011).

25.3.2.1 Ventilation Rates. Darkrooms require a minimum of 0.5 CFM of outdoor air per square foot of fl oor area (0.0026 m 3 /min/m 2 ) for ventilation. Alterna-tively, 8–10 ACH are suffi cient under most conditions. The key is to have local exhaust hoods to capture con-taminants at the source. Supply air outlets should be located so that they will not create drafts or cause short-circuiting of air into the exhaust air registers or systems. Long periods inside a closed, confi ned darkroom could be unpleasant without adequate ventilation. Therefore, a dynamic makeup air system should be included to heat and cool the darkroom and provide comfort condi-tions for those working there.

When calculating ventilation rates, it may be enough to match generation rate of contaminants with an ade-quate fl ow of dilution air (Crawley, 1985). A rule of thumb is to use 200 CFM (0.09 m 3 /s) per processing machine.

25.3.2.2 Local Exhaust. A covered tank requires little exhaust; approximately 25–30 CFM per square foot of tank area (0.12–0.15 m 3 /min/m 2 ) is adequate. However, an open tank requires an exhaust slot hood at the edge of the tank or in the middle, drawing 150–200 CFM per square foot of tank area (0.7–1.0 m 3 /min/m 2 ).

For processes using open trays of chemical solu-tions, lateral slot exhaust openings or an enclosure hood should be used. The Industrial Ventilation: A Manual of Recommended Practice for Design, 27th Edition (American Conference of Governmental Indus-trial Hygienists [ACGIH], 2010) contains design guid-ance. Local exhaust systems are used because they provide better control of fumes before they reach the breathing zone of workers. Examples are shown in Figures 25-8 and 25-9 .

FIGURE 25-8. Small hood for darkroom: Elevation and section (Sizes may vary according to specifi c applications).

48 Inches

ELEVATION SECTION

6 3/4 Inches

6 3/

4 In

ches

3 In

ches

1 1/

2 In

ches

1 In

ch

2

1

2

1

KEY

8 Inch Diameter ExhaustDuct

Exhaust Slot

Clean Air

Contaminated Air

1

2


FIGURE 25-9. Large hood for darkroom: Elevation and section (sizes may vary according to specifi c applications).

ELEVATION SECTION

48 Inches

18 In

ches

1 1/

2 In

ches

1 In

ch

3 Inches22

11

KEY

8 Inch Diameter Exhaust Duct

Exhaust Slot

Clean Air

Contaminated Air

1

2

25.4 LOSS PREVENTION, INDUSTRIAL HYGIENE, AND PERSONAL SAFETY

All recommendations contained in Section 4 of Chap-ters 1 and 2 should be reviewed and implemented.

25.4.1 Digital Imaging Rooms

25.4.1.1 Imaging Rooms with Magnetic Field ( MRI ). Signage to prevent personnel from entering a room con-taining an MRI scanner with ferrous or metallic objects is vital. Training of personnel who use these systems is paramount. Protective equipment such as fi re extin-guishers must be of aluminum construction. Similarly, compressed gas cylinders must also be nonferrous and properly color coded for easy identifi cation. Even then, it is necessary for the operator to have a magnetic wand to measure the magnetic fi eld to confi rm before any item is brought near the magnet. The 5-Gauss line around the magnet is usually considered to be a safety perimeter. Items inside are subjected to a potentially harmful magnetic fi eld.

25.4.1.2 Oxygen Detection in MRI Rooms. Because of the large quantities of cryogens used such as helium, it is necessary to have a continuous oxygen monitor in the imaging room to detect any decrease in oxygen levels due to a leak in the cryogen system. The location of these detectors is critical because they need to be able to detect oxygen defi ciency while at the same time not interfere with the operation of the imaging unit. They need to be in areas with adequate air movement and mixing. Some argue that imaging lab fi lling with cryogen. This can be any gas that is liquid at very cold temperatures and/or is under heavy pressure. In this case they are probably referring to cryogenic nitrogen. The detectors should be located at low level say 4 to 4.5 ft above the fi nished fl oor. The danger of these detectors getting damaged by room activity is greater if installed at lower levels.

25.4.1.3 Shielding in PET Rooms. Most commonly lead and/or concrete is used for area shielding in a PET facility. The attenuation factor necessary for shielding is likely to be no more than 10, but the high penetration of 511 keV photons can require a signi-

SPECIAL REQUIREMENTS 337

ASHRAE, 2011), there is a recommendation that pho-tographic products not be stored in damp basements or in high-temperature and high-humidity areas. The ideal storage temperature is 60°F (16°C) with a humidity range of 40–60%, with 40% RH being preferred. In tropical areas, refrigerated storage is recommended. Supplies should be kept in vapor-tight packages or placed in sealed containers. Black and white printing papers should be stored at 70°F (21°C) or below and color fi lm or paper at 45–50°F (7°–10°C). Long-term storage of color fi lm or papers at a temperature above 70°F (21°C) may affect color balance. When products are taken out of long-term storage, a warm-up time is necessary before use (ASHRAE, 2011).

25.5.1.2 Storage of Processed Film and Prints in Darkrooms. Usually, processed fi lm and prints are not stored in the darkroom because storage requirements make it hard for processing and storage to be conducted in the same room. ISO 18911, “Imaging Materials – Processed Safety, Photographic Film Storage Practice” (2000) provides guidance on three levels of storage: medium term, long term, and archival. Specifi c details for storage environments are available in the ASHRAE Applications Handbook, Chapter 22 (ASHRAE, 2011).

25.5.2 Plumbing

25.5.2.1 Imaging Room Plumbing. In general, no plumbing is provided in imaging rooms. However, in rooms containing a CT scanner or where ultrasound is performed hand-wash sinks are needed. Radioisotopes may be used in CT scan rooms and the gels applied in ultrasound procedures need to be washed off before technicians leave the room.

Many imaging facilities require access to a toilet in or near changing rooms for human subjects or patients.

25.5.2.2 Darkroom Plumbing. Wash water dis-charged from photographic processes contains chemi-cals that may not be discharged directly into the sewer system, unless the volume is truly trivial. For example, in radiology processing, where large amounts of x-ray fi lm are processed regularly, it will be cost effective to install a silver-recovery system. However, the chemicals used occasionally in a darkroom are unlikely to be large enough to warrant recovery. Plumbing fi xtures should be selected to provide suffi cient width, length, and depth

fi cant thickness of either material. Use of concrete may be expensive. Lead is readily available in the form of leaded wallboard and as plate and sheet stock for special construction.

As the operator will spend most time in the PET scanner control room, shielding of control room should be reviewed. In addition, the injection rooms and hot lab also require radiation shielding.

25.4.2 Darkrooms

It is important that all electrical receptacles near sinks be provided with ground fault current interrupter (GFCI) devices to prevent electrical shock hazards. Flooring should be nonskid to reduce the chance of falls due to spills and splashing. A safety shower and emer-gency eyewash are needed. Emergency eyewash foun-tains plumbed with tempered potable water should be installed in a large student darkroom.

The water supply to the rinsing bath should have backfl ow preventers to protect the building water supply from accidental contamination.

25.4.2.1 Personal Protective Equipment in Dark-rooms. Aprons face shields, safety glasses, goggles, and gloves should be used, and a convenient storage place should be provided for these items.

25.4.2.2 Chemical Exposure Hazards Darkrooms. The greatest health concern that results from continu-ous exposure to photographic chemicals is contact der-matitis or allergic contact dermatitis (ACD; Brancaccio, Cockerell, Belsito, & Ostreicher, 1993; McCann, 2005). Therefore, a high level of personal hygiene is called for, and washing facilities must be provided in the darkroom.

Most photographic darkrooms do not use chemicals in the quantities formerly used in medical x-ray fi lm processing, so the dangers of developing these problems are less likely. With the advent of digital processes, most hospitals and clinics have switched their practices.

25.5 SPECIAL REQUIREMENTS

All items described in Section 5 of Chapters 1 and 2 should be reviewed, and those that are relevant should be implemented.

25.5.1 Storage

25.5.1.1 Darkroom Storage of Unprocessed Products. In the ASHRAE Applications Handbook (Chapter 22 ,


25.5.3 Security 25.5.3.1 MRI Security. Three levels of security are required for MRI imaging rooms: (1) the room itself, (2) the control room, and (3) the surrounding laboratory or animal housing suite. All three must have controlled access.

for the number of trays that will normally be used. Thermostatic mixing valves that maintain the correct temperature will be needed. In addition, the water supply may require fi ltration to remove particulate matter; a 50- μ m fi lter is recommended.

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