Checker Signature on a Pressure-Receiver Repair Drawing
You are a mechanical engineer (EIT) at a 40-person consulting firm. A municipal client requires a 1.5 mm corrosion allowance on a compressed-air receiver. The senior engineer who is the engineer of record is on vacation; his nephew, a junior designer, prepared the repair drawing. The drawing shows 6.0 mm nominal wall, design pressure 2.5 MPa, inside radius 300 mm, allowable stress 138 MPa, and joint efficiency 0.85, but no corrosion allowance. Your quick check gives a required thickness of about 7.98 mm including allowance, so the 6.0 mm wall is under by roughly 2 mm. Your supervisor says, 'The client's Friday deadline is tight; just initial the checker box. The PE will seal it Monday.' You are not the PE of record and have not been asked to seal anything, but your initials would represent that the drawing was checked. The designer is a relative of the PE, and the client has already scheduled the repair outage.
1. Identify the ethical issues and the specific obligations that prevent you from simply initialing the checker box.
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The drawing omits the client-required 1.5 mm corrosion allowance. With P=2.5 MPa, r=300 mm, S=138 MPa, and E=0.85, the required thickness is t=Pr/(SE−0.6P)+CA=2.5(300)/(117.3−1.5)+1.5≈6.48+1.5=7.98 mm, which exceeds the 6.0 mm nominal wall. Initialing the checker box would falsely represent that a competent check was performed. Ethical obligations include public safety, competence, honesty in reports, avoiding conflicts of interest, and not signing or sealing work outside your authority. The family relationship with the designer and the Friday deadline increase the conflict; they do not reduce the duty.
2. Draft the actions you would take before Friday, including whom to notify and what to document.
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Do not initial the box. Prepare a written calculation showing the required thickness and the missing allowance, mark the drawing 'not checked-hold,' and notify your supervisor in writing. Contact the engineer of record or another qualified PE to review before the deadline. If neither is available, tell the client/project manager that the package cannot be certified Friday and state why. Document dates, messages, and the technical basis. Offer a compliant option: increase wall thickness, reduce design pressure, or obtain a client-approved variance with engineering justification.
3. The supervisor says the PE will seal it Monday anyway. Explain why that does not cure the problem and what you should do if the supervisor insists.
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A PE's later seal does not cure a false checker entry. The checker record is part of the quality process, and the PE may rely on it. If the supervisor insists, refuse to sign and escalate to the firm's quality manager or principal. If pressure continues, follow the firm's ethics and reporting procedure and, where public safety is imminent, notify the client or appropriate authority consistent with law and confidentiality. Keep the calculation file. Retaliation is a risk, but the professional obligation is not to certify work you have not checked.