Even though the law says it just deletes chapter 1 in the IBC it actually deletes all the ICC Chapter 1's and replaced it with Act 45 which takes over for Chapter 1 and which does adopt most parts of the ICC codes with many changes. PA should make its own code like NJ and CA. Most contractors and many inspectors are not aware of the changes PA made because they are not printed, and they are very hard to find in the PA UCC web site. Inspectors can inspect ignoring the changes because contractors will never know.
Yeah. I read Act 45, and I couldn't find ANY scoping in it. It says the [board? agency? Don't remember) "shall adopt regulations" to incorporate the ___ code (the original Act 45 adopted the BOCA Basic Building Code, and has since been updated to various ICC editions), but nowhere in Act 45 does it actually state the actual intent: that the building code shall regulate the design and construction of buildings.
This is a bigger problem than you might think. I started working in an architect's office in 1972. A year or three after I started, the state adopted the first edition of ANSI A117.1 for accessibility. It was adopted by act of the legislature, using language similar to Pennsylvania's Act 45. Quoting loosely from memory, the public act in our state said something like,"The State Building Inspector shall revise the State Building Code to incorporate as minimum standards for accessibility the requirements of ANSI A117.1." Our then-State Building Inspector was a nice guy, but he wasn't the sharpest knife in the drawer, he had just one assistant building inspector and I think his clerical staff was whoever the Department of Public Works could spare for an hour here and there, so he did what you might expect: he sent out a letter to all the building officials in the state (but NOT to the architects, or to the AIA chapter) that said, "Pursuant to Public Act xx-yyyy, from now on you shall enforce ANSI A117.1 for accessibility."
So building officials around the state started enforcing A117.1, and building started getting more accessible. Until a large developer in the eastern end of the state had a permit for a large multi-family building rejected because the design didn't comply with A117.1 for accessibility. The developer had a lawyer, and the lawyer did what lawyers do -- he asked why the plans were rejected, the building official sent him a copy of the State Building Inspector's letter and the lawyer then looked up Public Act xx-yyyy. Oops! The act clearly said "The State Building Inspector shall amend the State Building Code ..."
So it went to court, and the judge (correctly) ruled that the State Building Inspector had not revised the State Building Code, so ANSI A117.1 did not apply to the plaintiff's project.
In adopting the I-codes, my state heavily edits chapter 1, but they don't delete it. Without chapter 1 to establish scoping, unless the scoping is included in the enabling legislation (and I can't find it in PA Act 45), you can adopt whatever you want as a building code and make whatever amendments you want - but it won't apply to anything if a good lawyer bothers to read the law.
That said -- PA left the scoping in the IEBC, so that may be your ace up the sleeve.