I'm not an expert on this either but looking at the spec sheets for the two
different materials, I'd say you'd have to prove that the /24 will comply
with the requirements for /23. There are a number of differences between the
two.  Just looking at the descriptions:
(This is supposed to be a table with columns separated by "|")

/23                     |       /24
Epoxy                   |       Majority Epoxy
FR5                     |       FR4
Hot Strength Retention  |       N/A
Tg 135-175              |       Tg 150-200

You can find more comments about the difference between FR4 and FR5 in the
Technet Archives.  Fr-5 is typically used in applications with high
operating temperatures.

In addition to the different descriptions, the laminate requirements table
shows that /23 has higher requirements for peel strength, volume and surface
resistivity, dielectric breakdown and arc-resistance.

Perhaps with some of the improvements in FR4 materials, they now comply with
the higher standards for /23, but you or your material supplier would have
to prove that.

> ----------
> From:         Mark Hargreaves[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Mark Hargreaves
> Sent:         Friday, January 18, 2002 8:24 AM
> To:   [log in to unmask]
> Subject:      [TN] IPC-4101/23 vs /24
>
> Hi All,
> Does type GF/GFG material (IPC-4101 / 24) meet the requirements of type GH
> material (IPC-4101 / 23) ?
>
> Our customer is requesting type GH.  We stock type GF/GFG and would like
> to
> use it instead.
>
> (I hope I've phrased this properly.  4101 is a little over my head)
>
> Many Thanks,
> Mark Hargreaves
>
> --------------------------------------------------------------------------
> -------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt delivery of Technet send e-mail to [log in to unmask]:
> SET Technet NOMAIL
> To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
> E-mail Archives
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
> additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
> -------
>

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------