The weak link is usually 50 mm wide
Tape is part of the package, not a closing detail
A dissipative bag sealed with ordinary office tape has a strip of insulating material across it. The bag may still measure in range away from the tape, and fail at the seam where the tape sits.
The same applies to stretch film, bubble wrap and foam peanuts used as void fill. Any insulating material in contact with a sensitive board can hold charge that has nowhere to go.
Which markings carry meaning
The ESD warning symbol, the sensitivity classification and the moisture sensitivity level marking all convey information that downstream users act on. A supplier logo or a generic "antistatic" printed in a corner conveys nothing.
Where a bag is moisture barrier type, the MSL label and the desiccant and humidity indicator card are part of the specification, not optional extras. Removing them to save cost removes the reason the bag was chosen.
Auditing consumables
Consumables are bought in bulk and used without inspection, which is exactly why they drift. A simple receiving check on a sample of each lot, recorded against the purchase specification, catches the substitution of a standard tape for an ESD tape.
It also helps to keep the consumable specification on the line, not only in the QA folder: the person sealing the bag is the last chance to notice that the tape roll has changed colour.
FAQ
Can I use ordinary tape on an ESD bag?
It is not recommended. Standard tape is insulating and interrupts the path across the bag surface. Use tape specified as dissipative or antistatic for the application.
What does the ESD warning symbol mean?
It identifies a package or area where electrostatic sensitive devices are present and handling precautions apply. It is a handling instruction, not a certification of the packaging performance.
Are printed labels a static risk?
Ordinary paper or film labels can be insulating. Where labels sit on a dissipative bag inside a sensitive assembly, specify labels that are compatible with the packaging system.
How do I check incoming consumables?
Sample each lot against the purchase specification, test resistance where the item claims a resistance range, and keep the record with the lot number.
All figures above refer to standard product data sheets; final confirmation is subject to written quotation.