How to Hang Pipe from Extremely Old Wood?

4/12/2023

What concerns should I have about hanging from old wood?

Like very old wood, almost petrified?

I'm doing an NFPA 13R job for an old historic building that has been moved. I don't know how old, but it uses full dimension wood. The 2x's look like they measure 2-inches thick.

I'm wondering what hanging to this old dry wood is going to be like?

Do they need to predrill? Are screws better?

Any ideas appreciated!

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11 Comments

Todd E Wyatt

4/12/2023 07:25:31 am

Per NFPA 13D, piping support shall be per its listing limitations. If the listed pipe does not include piping support requirements, it shall be supported “from structural members using support methods comparable to those required by applicable local plumbing codes.”

2021 IPC Section 308 Piping Support includes prescriptive requirements including structural attachment, interval of support, and hangar spacing.

REFERENCES
2022 NFPA 13D
Chapter 7 Installation
7.4 Piping Support.
7.4.1
Listed pipe shall be supported in accordance with any listing limitations.
7.4.2
Pipe that is not listed, and listed pipe with listing limitations that do not include piping support requirements, shall be supported from structural members using support methods comparable to those required by applicable local plumbing codes.

2021 IPC
Chapter 3 General Regulations
About this chapter: Chapter 3 covers general regulations for plumbing installations. As many of these requirements would need to be repeated in Chapters 3 through 14, placing such requirements in only one location eliminates code development coordination issues associated with the same requirement in multiple locations. These general requirements can be superseded by more specific requirements for certain applications in Chapters 3 through 14.

Section 308 Piping Support
308.1 General
Plumbing piping shall be supported in accordance with this section.
308.2 Piping Seismic Supports
Where earthquake loads are applicable in accordance with the International Building Code, plumbing piping supports, anchorage, and bracing shall be designed and installed for seismic forces in accordance with Chapter 16 of the International Building Code.
308.3 Materials
Hangers, anchors and supports shall support the piping and the contents of the piping. Hangers and strapping material shall be of approved material that will not promote galvanic action.
308.4 Structural Attachment
Hangers and anchors shall be attached to the building construction in an approved manner.
308.5 Interval of Support
Pipe shall be supported in accordance with Table 308.5.
Exception: The interval of support for piping systems designed to provide for expansion/contraction shall conform to the engineered design in accordance with Section 316.1.
TABLE 308.5 HANGER SPACING
308.6 Sway Bracing
Where horizontal pipes 4 inches (102 mm) and larger convey drainage or waste, and where a pipe fitting in that piping changes the flow direction greater than 45 degrees (0.79 rad), rigid bracing or other rigid support arrangements shall be installed to resist movement of the upstream pipe in the direction of pipe flow. A change of flow direction into a vertical pipe shall not require the upstream pipe to be braced.
308.7 Anchorage
Anchorage shall be provided to restrain drainage piping from axial movement.
308.7.1 Location
For pipe sizes greater than 4 inches (102 mm), restraints shall be provided for drain pipes at all changes in direction and at all changes in diameter greater than two pipe sizes. Braces, blocks, rodding and other suitable methods as specified by the coupling manufacturer shall be utilized.
308.8 Expansion Joint Fittings
Expansion joint fittings shall be used only where necessary to provide for expansion and contraction of the pipes. Expansion joint fittings shall be of the typical material suitable for use with the type of piping in which such fittings are installed.
308.9 Parallel Water Distribution Systems
Piping bundles for manifold systems shall be supported in accordance with Table 308.5. Support at changes in direction shall be in accordance with the manufacturer's instructions. Where hot water piping is bundled with cold water piping, hot water piping shall be insulated in accordance with Section 607.5.
308.10 Thermal Expansion Tanks
A thermal expansion tank shall be supported in accordance with the manufacturer's instructions. Thermal expansion tanks shall not be supported by the piping that connects to such tanks.

Dan Wilder

4/12/2023 07:42:00 am

Honestly, that will probably be the best install that will have the least amount of splitting wood install. Even the old building wood in Phoenix that is super dry after 70+ years does better than the new lightweight framing common in new builds.

Install should be per MFG direction/recommendations as to predrilling.

Ray Hardy link

4/12/2023 08:11:54 am

Drill for an eyebolt and fix a back-plate for stability I would think. Coach-bolts where you can. Maybe consider some additional fixings to spread the point loading. I'd be selective where I ran the distribution mains and certainly consider double point fixings.

Ray Jackson link

4/12/2023 08:16:12 am

Could you place a 2 x 4 on top of the existing and use that for your hanging points?

Casey Milhorn

4/12/2023 08:21:05 am

I prefer side sammys over the straight ones, especially if you are concerned with "pull out". They also allow for adjustment of rod without having to recut, or cut too exact in the first place.

If you have concerns over the ability of the structure to support the weight of the water filled pipe or pull out of attachment, definitely get the structural engineer involved (if there is one), if not the architect would probably be the correct person to get the RFI.

Adam

4/12/2023 09:16:56 am

I have been involved in the substantial renovation of several century buildings.

In my experience, these older buildings with rough sawn lumber framing which used to support lath-and-plaster finishes are more substantially built than modern wood-frame buildings. The conversation could be reversed - I would have more concern over modern wood-frame structures failing under normal conditions!

You would need to check bearing points of the members, since this is where your weakest link would likely be. Sometimes joists are side-nailed to studs when ballon-framed, but overall, I would not be concerned with the load-bearing capacity or splitting potential of these structures.

Anthony

4/12/2023 09:50:06 am

The question if the building can hold load is a question for the architect and structural engineer of the project. They need to take responsibility for the 'fitness' of the structure and for stability and occupancy.

If you're unsure if you can screw into the wood, I'd suggest using side Sammy's or through bolts and angle nuts on strut.

Glenn Berger

4/12/2023 11:12:19 am

I fully recommend consulting with a structural engineer prior to executing the installation.

Dave

4/12/2023 11:20:04 am

I have always consulted with my more experienced fitters before listing, then list an assortment but of the many historic (by west coast standards) structures I have enjoyed working on, with better-quality tight-grained wood, I have not had negative feedback from fitters on hanging. I agree with Casey on the side-Sammys, and Sammys in general due to small diameter, Coach Screws with pre-drilling in some places, and ceiling flanges where it makes sense. CAution is prudent, but I wouldn't make it more complicated / expensive / time-consuming than it needs to be. As Anthony said, the structure is up the the architect and structural, just add your usual disclaimers.

SCHULMAN

4/12/2023 11:36:04 am

I have found old wood to be superior originally and stronger now than any new wood ever is.

Alex

4/12/2023 10:48:05 pm

Hate to be the one to defer the question, but I would consult a structural engineer. You want to make sure the wood is still in good shape and can handle the additional load.

How to Hang Pipe from Extremely Old Wood?

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