Every attempt is made for accuracy in every portion of the guide.
It pains me to find mistakes, but I post them here in an effort for complete clarity and most importantly to aid in better exam prep. All of these updates are shown below for your aid in preparing for the exam and are also incorporated in future editions of the Prep Guide. We hope you find this helpful.
2021 PE Prep Guide Errata:
Units (p43): Compartment Mass Ventilation Rate should also list kg/s.
Problem 03 (p114): Each component in the problem should have a "probability of failure" and not a "failure rate". These are two separate terms, and mean two different things. In this problem, for example, OS&Y valve should say "closed/failed: 0.5% probability of failure."
Although the failure rate, λ(t), is often thought of as the probability that a failure occurs in a specified interval, it is not actually a probability because it can exceed 1.0. A probability, on the other hand, cannot exceed 100%. Problems asking for "probability of failure or success" are different than problems asking for a "failure rate" or "success rate" of a system.
Problem 14 (p131): Conversion for Compartment Mass Ventilation Rate should read kg/s=CFMx0.3048^3 x 1.18 kg/m^3 x (1/60s)
Problem 96 (p242): The question should not include a density near the door. It is not necessary for the problem and conflicts with the assumed specific flow.
Problem 105 (p265): The ranking order in the solution is backwards. Plywood is least resistive and two layers of 1/2-inch gypsum is most resistive.
Problem 108 (p268): The effective width needs to have a 6-inch boundary layer on both sides of the door, making the effective width 4.5-feet. This would change the solution to 1.2 minutes instead of 1.1 minutes.
Problem 183 (p352): Answer should be 1,189 cubic feet per second, not cubic feet per minute.
[End of Errata]
It pains me to find mistakes, but I post them here in an effort for complete clarity and most importantly to aid in better exam prep. All of these updates are shown below for your aid in preparing for the exam and are also incorporated in future editions of the Prep Guide. We hope you find this helpful.
2021 PE Prep Guide Errata:
Units (p43): Compartment Mass Ventilation Rate should also list kg/s.
Problem 03 (p114): Each component in the problem should have a "probability of failure" and not a "failure rate". These are two separate terms, and mean two different things. In this problem, for example, OS&Y valve should say "closed/failed: 0.5% probability of failure."
Although the failure rate, λ(t), is often thought of as the probability that a failure occurs in a specified interval, it is not actually a probability because it can exceed 1.0. A probability, on the other hand, cannot exceed 100%. Problems asking for "probability of failure or success" are different than problems asking for a "failure rate" or "success rate" of a system.
Problem 14 (p131): Conversion for Compartment Mass Ventilation Rate should read kg/s=CFMx0.3048^3 x 1.18 kg/m^3 x (1/60s)
Problem 96 (p242): The question should not include a density near the door. It is not necessary for the problem and conflicts with the assumed specific flow.
Problem 105 (p265): The ranking order in the solution is backwards. Plywood is least resistive and two layers of 1/2-inch gypsum is most resistive.
Problem 108 (p268): The effective width needs to have a 6-inch boundary layer on both sides of the door, making the effective width 4.5-feet. This would change the solution to 1.2 minutes instead of 1.1 minutes.
Problem 183 (p352): Answer should be 1,189 cubic feet per second, not cubic feet per minute.
[End of Errata]
