There are codes, there are perceived hazards and there are real hazards we must consider with any situation when deciding what to report or call out. This is a case where there is no clear cut answer in any of the codes. You are allowed gas pipes into woodburning fireplaces either for log lighters or gas logs, whether vented or ventfree. If the fireplace is factory built, it must allow such gas pipes, it must have a conduit provided for such piping, and it must state in the listed instructions what appliances are approved for use in their fireplace such as log lighters, vented logs and ventfree logs.

As Gunnar noted, I have found a significant incidence rate of fugitive gas leaks with the old style key valves, which take 21 throws of the wrist. I have not noticed hardly any leaks from the newer 1/4 turn non-displaceable fully ported ball valve type. This includes leaks downstream within the piping and into the room. I guess things are getting better for a change.

The codes do not address the issue of stubbing out a gas line into a masonry fireplace or capping off the line to an appliance. I, too was concerned about this issue so I called Ted Lemoff, who wrote NFPA 54 and is their staff technical advisor. He assured me if there was a single incident involving gas captured btw the shutoff and cap in the firebox leading to a single fire or explosion, it would be addressed in the codes. The only thing they caution is not to allow gas piping to be exposed to full flame impingement. For instance, log lighters miraculously have an excellent safety record in spite of their potential for problems. Deliberately building a wood fire on top of the log lighter nightly seems crazy to me but they just don't blow up.

The larger hazard here is if the pipe penetration is not properly sealed to the refractory panel and the inner firebox wall at the conduit.

That facing and mantel seem awfully skinnny at the sides of the firebox. Aside from looking disproportionate, you need to check the listed instructions. Most factory builts do not state a flat requirement for non-combustible surrounding the sides but rather use a formula such as anything combustible must be in the shaded zone of an illustration. This uses a triangle formed from the rear corner of the firebox to the opposing outer edge of the firebox. For flush facings, it may work out to about a 38 degree angle and about 54 degrees for a 4 inch brick facing, as one example. Again, this varies by mfr. and even model.

I can't tell if the marble hearth extension is above the floor or not. When you see flush HX, suspect no required insulation board under the HX. Again, consult the listed instructions.

HTh,
Bob

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Keep the fire inside the fireplace!
IAFCI Regional Director & Certified Fireplace Inspector
Certified Master Hearth Professional & HPBA BoD