AskCodeMan

Hi Jerry,

I like to thank you for this website and your time.

AC condenser unit low side pipe insulation. What type and R rating of pipe insulation of new ac system. In the old day we see smaller size insulation, now day I have seen many thicker type pipe insulation but also still see many smaller pipes insulation. What is the right type pipe insulation and do you have any picture?

Hi Richard,

From the 2004 FBC, Residential.
- M1411.4 Insulation of refrigerant piping.
- - Piping and fittings for refrigerant vapor (suction) lines shall be insulated with insulation having a thermal resistivity of at least R = 4.0 hr · ft2 · °F/Btu and having external surface permeance not exceeding 0.05 perm [2.87 ng/(s · m2 · Pa)] when tested in accordance with ASTM E 96.

As to what type of insulation that is, as long as it is marked stating that it meets ASTM E 96, that is all we can look for.

Sorry, no photo.

Hi Richard,

Here is another code reference from the Florida Building Code, Building, Chapter 13, Energy Efficiency, applicable to both the FBC-B and FBC-R.

- 13-611.1.ABC.1 Piping insulation.
- - All piping installed to service buildings and within buildings, including the vapor line of HVAC refrigerant piping, shall be thermally insulated in accordance with Table 611.1.ABC.1, except as stated herein (for service water heating systems, see Section 612.1.ABC.5).
- - - Exceptions: Piping insulation is not required in the following cases:
- - - - 1. Piping installed within HVAC equipment.
- - - - 2. Piping containing fluid at temperatures between 55°F and 120°F (13°C to 49°C).
- - - - 3. Piping within the conditioned space.
- - - - 4. Piping within basements or unvented crawl spaces (plenums) having insulated walls.
- - - (from Table 611.1.ABC.1, posted information limited to refrigerant lines)
- - - TABLE 611.1.ABC.1
- - - - MINIMUM PIPE INSULATION
- - - - - Piping System Types - - Fluid Temperature - - Runouts2 - - Insulation for Pipe - - Thickness Sizes1
- - - - - - - - - - - - - - - - - - - - - - - - Range°F - - - - - - (inches) - - - - - - < 1" - - - - - - - - - - - 1.25 - 2"
- - - - - Chilled water, refrigerant
- - - - - or brine - - - - - - - - - - - - - - Below 40 - - - - - - - 1.0 - - - - - - - - 1.0 - - - - - - - - - - - - 1.5
- - - - For SI: 1 inch = 25.4 mm, °C = [(°F)-32]/1.8.
- - - - 1. For piping larger than 1 inch diameter and exposed to outdoor ambient temperatures, increase thickness by 0.5 inch.
- - - - 2. Runouts to individual thermal units (not exceeding 12 feet in length).
- - - - 3. The required minimum thicknesses do not consider water vapor transmission and condensation. Additional insulation, vapor retarders, or both, may be required to limit water vapor transmission and condensation.