Biological safety cabinet (BSC) 1: Introduction — Transcript

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1. 0:04biological safety cabinets or BSC's are
2. 0:07designed to protect laboratory workers
3. 0:09and the surrounding environment from
4. 0:11pathogens it is important that everyone
5. 0:14working in a BSc understands when they
6. 0:17should be used how they work and how to
7. 0:19use them correctly BSC's provide
8. 0:22effective primary containment for work
9. 0:24with infectious material if they are
10. 0:26properly maintained and used in
11. 0:28combination with good laboratory
12. 0:30techniques a risk assessment should be
13. 0:32performed to determine whether a BSC is
14. 0:35required for each activity conducted in
15. 0:37your facility in general a BSC should be
16. 0:41used when the activities increase the
17. 0:43likelihood of exposure to pathogens and
18. 0:45when the consequences of such an
19. 0:47exposure could be serious to either the
20. 0:50lab personnel or the environment for
21. 0:52example a BSC can significantly reduce
22. 0:55the risk when handling open vessels of
23. 0:57pathogens transmitted via the inhalation
24. 0:59route and when manipulating large
25. 1:02volumes or highly concentrated
26. 1:03infectious agents personnel protection
27. 1:06is provided by BSC's through a
28. 1:08continuous stream of inward air known as
29. 1:11inflow which helps prevent aerosols from
30. 1:13escaping through the front opening
31. 1:16contaminated air is exhausted through
32. 1:18high-efficiency particulate air filters
33. 1:20or hepa filters before being released in
34. 1:23the environment certain types of BSC s
35. 1:26also protect the samples from becoming
36. 1:28contaminated when working with them
37. 1:30these cabinets use HEPA filtered down
38. 1:33flow air to flush the cabinet interior
39. 1:35of airborne contaminants and to prevent
40. 1:37unfiltered inflow air from entering the
41. 1:40work area it is important not to confuse
42. 1:43BSC s with other ventilated enclosures
43. 1:46commonly found in laboratories such as
44. 1:48fume hoods and laminar flow cabinets
45. 1:51which should never be used for personal
46. 1:53protection against working with samples
47. 1:55containing pathogens
48. 1:57there are many classes and types of BS
49. 1:59CS that offer varying levels of
50. 2:01protection class 1b SCS provide
51. 2:05personnel and environmental protection
52. 2:07by drawing-room air into the cabinet
53. 2:09through the front opening across the
54. 2:11workspace and then discharging it from
55. 2:13the cabinet through a HEPA filter the
56. 2:16filtered exhaust air can be recirculated
57. 2:18into the laboratory or exhausted
58. 2:20directly to the outside atmosphere if it
59. 2:22is hard ducted to the facility's HVAC
60. 2:25system it is possible to work safely
61. 2:28with small quantities of volatile toxic
62. 2:30chemicals
63. 2:31if the BSC is hard ducted class 1b SCS
64. 2:35are generally recommended for procedures
65. 2:37where total sterility of the biological
66. 2:39material is not a critical factor these
67. 2:42cabinets are often used for disposal of
68. 2:45infectious waste placing samples in
69. 2:47disinfectant and cage dumping or
70. 2:49activities where infectious material
71. 2:52won't be open but the risks of aerosol
72. 2:54generation in the event of a malfunction
73. 2:56are high homogeneous ation is one
74. 2:59example of a process ideally suited for
75. 3:02a class 1 BSC however in situations
76. 3:05where no class 2 BSC is available there
77. 3:09are other scenarios where class 1b SCS
78. 3:12can be considered despite the lack of
79. 3:14sample protection these include
80. 3:16processes were the risk to personnel in
81. 3:18the environment outweigh the need for
82. 3:20sterility preparation of tissue sections
83. 3:23for formal and fixation mechanical
84. 3:26disruption of tissue with mortar and
85. 3:28pestle addition of liquid samples or
86. 3:30homogenates to inactivating agents for
87. 3:33downstream nucleic acid or protein
88. 3:35purification and preparation of smears
89. 3:38for tuberculosis or rabies diagnosis are
90. 3:41a few examples where even without
91. 3:43product protection the likelihood of a
92. 3:45negatively impacted end product or test
93. 3:47result is low other activities such as
94. 3:50cell culture virus isolation or
95. 3:53manipulation of extracted nucleic acids
96. 3:56should never be performed in a class 1
97. 3:59BSC since the unfiltered air blowing
98. 4:02over the work surface is likely to
99. 4:03result in contamination loss of sample
100. 4:06integrity and ultimately unreliable
101. 4:09results class to be SCS provide
102. 4:12personnel and environmental protection
103. 4:15however unlike class 1b SCS
104. 4:18they also offer product protection by
105. 4:20filtering all air that passes through
106. 4:22the front grills before distributing it
107. 4:24over the work surface class 2b SCS are
108. 4:27further divided into four types a 1 a 2
109. 4:31B 1 and B 2 which differ according to in
110. 4:36flow velocities recycling of cabinet air
111. 4:38and connections to building exhaust
112. 4:40systems class 2 type a1 and a2 cabinets
113. 4:45are the most commonly encountered BSC s
114. 4:47in microbiology Laboratories these
115. 4:50cabinets recirculate 70% of HEPA
116. 4:53filtered air flow back into the cabinet
117. 4:55and exhaust the remaining air out of the
118. 4:57cabinet through a second HEPA filter
119. 4:59directly into the room class 2 type B
120. 5:02cabinets differ from type a in they're
121. 5:04higher in flow velocities and direct
122. 5:06connection to the building's exhaust
123. 5:08system class 2b ones recycle about 50%
124. 5:12of HEPA filtered air back into the
125. 5:14cabinet therefore work with only low
126. 5:16levels of volatile toxic chemicals and
127. 5:19trace amounts of radionuclides may be
128. 5:21performed class 2b 2's discharge 100% of
129. 5:25HEPA filtered cabinet air out through
130. 5:27the building's exhaust system and
131. 5:29therefore work with volatile toxic
132. 5:31chemicals and radionuclides may be
133. 5:33performed while these cabinets provide
134. 5:36excellent levels of protection they have
135. 5:38higher electrical consumption more
136. 5:40complex installation requirements and
137. 5:42increased overall lifetime running costs
138. 5:45compared to type a cabinets all of these
139. 5:48factors should be considered when a
140. 5:50facility is preparing to purchase a BSC
141. 5:52class 3 BS CS provide the maximum level
142. 5:56of personnel and environmental
143. 5:58protection they are completely enclosed
144. 6:00and are kept under negative pressure
145. 6:02these highly complex containment devices
146. 6:05are typically reserved for pathogens and
147. 6:07procedures where the consequence of a
148. 6:09laboratory exposure or environmental
149. 6:12release could be severe due to high
150. 6:14associated more tau
151. 6:15and transmissibility combined with a
152. 6:17lack of effective treatment or
153. 6:19prophylaxis all biosafety cabinets must
154. 6:23be certified by manufacturers for
155. 6:25compliance with a set of performance
156. 6:26standards for BSC s these can vary
157. 6:29depending on the manufacturer's country
158. 6:32of origin but are typically NSF
159. 6:34international or the European Committee
160. 6:36for Standardization ideally BSC should
161. 6:40also be certified on-site after
162. 6:42installation and on an annual basis to
163. 6:45ensure that supply and exhaust HEPA
164. 6:47filters are functioning correctly and
165. 6:49directional air flow is being maintained
166. 6:52finally careful consideration must be
167. 6:55given to where the BSC is installed
168. 6:57within the room as a general rule select
169. 7:01a location where minimal disturbance to
170. 7:03air flow will occur to ensure its
171. 7:05maximum effectiveness
172. 7:06BSC s should not be located in
173. 7:09high-traffic areas or directly opposite
174. 7:11of seated workstations and a minimum
175. 7:14distance must be maintained from other
176. 7:16BSC's or chemical fume hoods to avoid
177. 7:19disruption of the air curtain a local
178. 7:21risk assessment will help determine a
179. 7:23reasonably safe distance to avoid
180. 7:25operation collision let us conclude this
181. 7:29video with a review of the following key
182. 7:31messages BSC's provide effective primary
183. 7:35containment for work with infectious
184. 7:37material if they are properly maintained
185. 7:39and used in combination with good
186. 7:41laboratory techniques there are many
187. 7:43classes and types of BSC s that offer
188. 7:46varying levels of protection a risk
189. 7:48assessment will help determine which one
190. 7:50is best suited for your laboratory and
191. 7:52for the types of activities you will be
192. 7:54conducting BSC s should be installed in
193. 7:57areas with minimal foot traffic and
194. 7:59potential airflow disturbances regular
195. 8:02on-site recertification ensures proper
196. 8:05functioning critical components
197. 8:06including air flow profiles and hepa
198. 8:08filters everyone working in a BSC should
199. 8:12understand how they work when they
200. 8:14should be used and how to use them
201. 8:16correctly
202. 8:17knowledge of how a BSc works is a key
203. 8:20component to working safely when using
204. 8:22them
205. 8:25you