Proper Location to Sample Antifreeze?

2/23/2023

What is the proper point in a system to take the antifreeze sample?

I have taken readings at both outlets at the check valve, unfortunately a contractor is saying to take it at the most remote point. Those locations are either 25-feet in the air, or not installed at all.

Thanks in advance.

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2 Comments

Dan Wilder

2/23/2023 08:14:36 am

You are both correct per NFPA 25 - 23' Edition
However, system size plays a role. Sounds like a secondary letter of recommendation needs to be sent to add a remote inspection point but read the appendix as this may cause dilution between the upper and lower sections of the pipe which is the intent of the higher testing point.

5.3.4.1 The antifreeze solution shall be tested at its most remote portion and where it interfaces with the wet pipe system.

5.3.4.2 Where antifreeze systems have a capacity larger than 150 gal (568 L), tests at one additional point for every 100 gal (379 L) shall be conducted.

A.5.3.4
Sampling from the top and bottom of the system helps to determine if the solution has settled. Antifreeze solutions are heavier than water. If the antifreeze compound is separating from the water due to poor mixing, it will exhibit a higher concentration in the lower portion of the system than in the upper portion. If the concentration is acceptable near the top, but too low near the water connection, it might mean the system is becoming diluted near the water supply. If the concentration is either too high or too low in both the samples, it might mean the wrong concentration was added to the system.

Todd E Wyatt

2/23/2023 09:20:49 am

A similar prescriptive requirement for the “test connection(s)” for “Antifreeze systems” is referenced in “2022 NFPA 13 — Standard for the Installation of Sprinkler Systems” which references “2020 NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems.”

REFERENCES
2022 NFPA 13 — Standard for the Installation of Sprinkler Systems
Chapter 8 System Types and Requirements
8.6* Antifreeze Systems.
A.8.6
In cold climates and areas where the potential for freezing of pipes is a concern, options other than antifreeze are available. Such options include installing the pipe in warm spaces, tenting insulation over the piping [as illustrated in Figure A.9.9.1(a) through Figure A.9.9.1(f) of NFPA 13D], listed heat tracing, and the use of dry pipe systems and preaction systems.

ENHANCED CONTENT
Antifreeze systems often are used as subsystems of a wet pipe system. Antifreeze systems are similar to wet systems, but they are not classified as wet systems. These systems are intended to protect small areas that could be exposed to freezing temperatures, such as outside loading docks. Antifreeze systems also are used for larger areas such as freezers, as well as for residential areas that are not protected against freezing temperatures.

Antifreeze systems were once economically more appealing than dry pipe systems for protecting small areas. The reduction in size and cost of certain dry pipe valves, combined with the added expense of backflow preventers and expansion chambers, has made antifreeze systems somewhat less appealing. However, since the hydraulic calculations for an antifreeze system can take the design area reductions of a wet system, there are situations in which the antifreeze system is more economical. Even where a backflow preventer is not required, a larger area protected with a dry pipe system could still provide a more economical option due to the cost of antifreeze for larger systems.

In August 2009, a fire in Truckee, California, brought to light potential problems with the combustibility of antifreeze solutions. In that case, an antifreeze solution was atomized through a discharging sprinkler and exploded, resulting in a fatality. After the Truckee incident, research performed on antifreeze solutions used in sprinkler systems resulted in the issuance of a Tentative Interim Agreement (TIA) by the NFPA Standards Council in August 2012 that prohibited the use of traditional antifreeze solutions in favor of listed solutions that will not ignite. While the original problem was brought to light in a residential occupancy with residential sprinklers, the testing found similar problems in nonresidential commercial applications with standard spray sprinklers.

8.6.3.6*
A drain/test connection shall be installed at the most remote portion of the system.
A.8.6.3.6
Systems are required by NFPA 25 to have the concentration levels checked at the supply inlet to the antifreeze system and at a remote point of the system.
8.6.3.7
For systems with a capacity larger than 150 gal (570 L), an additional test connection shall be provided for every additional 150 gal (570 L).

ENHANCED CONTENT
Checking the concentration level of the antifreeze solution only at the inlet to the system does not necessarily confirm that the solution in the remote portions of the system is at an acceptable level. To facilitate taking a sample, an additional test connection is required at the remote portion of the system. Additional test connections are also required for larger systems. Checking the additional locations is required by NFPA 25, as discussed in A.8.6.3.6.

2020 NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems
Chapter 5 — Sprinkler Systems
5.3.4* Antifreeze Systems.
5.3.4.1
The antifreeze solution shall be tested at its most remote portion and where it interfaces with the wet pipe system.
5.3.4.2
Where antifreeze systems have a capacity larger than 150 gal (568 L), tests at one additional point for every 100 gal (379 L) shall be made.
5.3.4.2.1
If the results indicate an incorrect freeze point at any point in the system, the system shall be drained and refilled with new premixed antifreeze.
5.3.4.2.2
For premixed solutions, the manufacturer’s instructions shall be permitted to be used with regard to the number of test points and the refill procedure.

Chapter 8 Fire Pumps
8.6 Component Replacement Testing Requirements.
There is no “A.8.6.3.6.”

Proper Location to Sample Antifreeze?

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