Prueba de Refractometro

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001330

FOAM CONCENTRATES AND

FOAM PRE-MIX SOLUTIONSField Inspection Manual



INTRODUCTION

This manual is designed to serve as a guide to inspectionprocedures for ANSUL Foam Concentrates and Pre-mixSolutions.

As Tyco Fire Protection Products manufactures many typesof foam concentrates, locate the product data sheet for thespecific concentrate to be tested. Product Data Sheets canbe accessed at .(,&.!)'.

The designated inspector should be a responsible, experi-enced person with sound, basic knowledge of fire equip-ment hardware and extinguishing agents. A thoroughbriefing on the procedures to be followed should include theneed for precise execution of each analysis step.

See Field Inspection Record at the end of this manual torecord proportioning results.

Form Part No. 428680, Foam Analysis Request, is for usein recording the information required when sending in

samples to the Tyco Fire Protection Products AgentsLaboratory. This form also outlines the correct procedurefor submitting samples. Review and complete the form asthoroughly as possible. This form is included in the FoamAgent Test Kit, Part No. 428679. It is also available onwww.ansul.com under “Foam Products.” (N)-": There is acharge for this testing service.)

FReqUeNCy aND aCCURaCy OF TesTs

Tyco Fire Protection Products recommends that proportion-ing tests be done at system commissioning and every three(3) years minimum thereafter.

e!"*-%)(: Pre-primed foam-water sprinkler systems

should be flushed, drained and pre-primed with fresh solu-tion annually. During this process correct proportioningshould be verified.

Tyco Fire Protection Products recommends that StandardQuality Analysis Testing be done annually by the Tyco FireProtection Products Agents Laboratory which not only teststhe chemical properties of the sample, but also does labscale fire testing to assure the product’s performance.Packages of two (2) sample containers with labels can bepurchased under Part No. 428679.

sTORage CONDITIONs

Tyco Fire Protection Products recommends that its concen-trates be stored at the temperatures indicated on thespecific product data sheet.

Accelerated aging studies have been conducted with theconcentrate and pre-mix solutions stored at 150 °F(65.5 °C) with no adverse effect. However, UnderwritersLaboratory Standard No. 162 requires that the maximumstorage temperature be listed at 120 °F (48.9 °C).

Storage of concentrates below the minimum temperaturelisted on the product data sheets could result in freezing. Ifthe agent freezes, it should be thawed at or near roomtemperature and agitated or stirred to ensure a homoge-nous mixture. If previous freezing is suspect, agitation wil

again ensure a homogenous mixture.To maximize life of concentrates stored in atmosphericstorage tanks, ANSUL recommends that a 1/4 in. (6 mm)layer of mineral oil be added to the air-exposed surface ofthe concentrate. This is critical for Alcohol ResistantConcentrates.

RelaTeD INFORmaTION

The following is a list of Technical Bulletins that can befound at the ANSUL internet home page .(,&.!)'.

• Technical Bulletin Number 52(Environmental Impact of ANSULITE AFFF Products)

• Technical Bulletin Number 54(Shelf Life of ANSULITE AFFF Concentrates and TheirPre-mixed Solutions)

• Technical Bulletin Number 55(Aspirated Versus Nonaspirated AFFF)

• Technical Bulletin Number 59(Acceptable Materials of Construction For Use WithANSUL Foam Concentrates)

• Technical Bulletin Number 60(Foam and The Environment)

• Technical Bulletin Number 64(Compatibility of AFFF/Alcohol-Resistant AFFFConcentrates)

ReFRaCTIve INDex vs. CONDUCTIvITy

Tyco Fire Protection Products recommends refractive indextesting instead of conductivity testing in the field becausethere is less chance of results being skewed by waterquality or temperature. Also, continuous stirring is requiredduring conductivity testing to obtain stable results.

INTRODUCTION

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FOam sOlUTION CONCeNTRaTION DeTeRmINaTION

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FOam sOlUTION CONCeNTRaTION DeTeRmINaTIONReFRaCTIve INDex OR CONDUCTIvITy

This test is used to determine the percent concentrate of afoam concentrate in the water being used to generate foam.It is typically used as a means to determine the accuracy of

the system’s proportioning equipment.

This method is based upon comparing foam solution testsample to pre-measured solutions (Calibration Standard)that are plotted on a baseline graph of percent concentra-tion versus instrument reading.

A hand-held refractometer is used to measure the refractiveindex of the foam solution sample. Scales on refractome-ters vary, but what is actually being used to determineconcentration is a change in reading from one pre-measured solution to another (Calibration Standards“Curve” vs. Discharge Samples “Reading”). The philosophyapplies when using a conductivity meter which is measuringthe changes in the solution’s conductivity. (Refer to

Proportioning Test Instruments Data Sheet, F-2007003, formore detailed information about the specific meters.)

A base curve is prepared by using the following apparatus:

1. Four 100 ml or larger plastic bottles with leak-resistantscrew caps

2. One 10 ml (10 cc) measuring syringe

3. One 100 ml graduated cylinder

4. Four or more eye droppers

5. One Test Meter – Model PA 202, 10419, 1500-32

6. Graph paper

7. Ruler or straight edge

Using water and foam concentrate from the system to betested, make up three 100 ml calibration standard solutions.For a 6% concentrate, typically a 4%, 6% and 8% samples;for a 3% concentrate, typically a 2%, 3% and 4% samples;and for a 1% concentrate, typically a 0.5%, 1% and 1.5%samples are made.

Label bottles with percent sample calibration solution thatwill be utilized, i.e. 2%, 3% and 4% for a 3% concentrate.As an example, for the 2% calibration solution sample,measure 98 ml of system water in the graduate cylinder,then pour into the bottle labeled 2%. Then with the measur-ing syringe, transfer 2 ml (2 cc) of the concentrate into thelabeled bottle. Secure the cap on the bottle and shake to

thoroughly mix the solution. Repeat for the 3% calibrationsample (97 ml water and 3 ml concentrate) and for the 4%calibration sample (96 ml water and 4 ml concentrate).I(!+",%(# ,'*&" ,%", %&& %(!+"," !!+!2 +"&-%/"-) -$" '",+"'"(- %(,-+'"(-. After thoroughly mixingthe foam sample, a meter reading is taken of each percent-age foam solution sample. It is important that temperaturesbetween discharge samples and calibration standards havenormalized with temperatures above 50 °F (10 °C) workingbest. Each instrument has specific instructions for itscorrect operation.

Using the graph paper, plot the meter reading on the X axisand the percent concentrate reading on the Y axis. Thisplotted curve will serve as the known baseline for theproportioning test. Meters may have different scales andthe plotted resolution should be as large as possible with

the complete range of the calibration solutions known. Thescale you set must be linear.

Collect foam solution sample(s) from the proportioningsystem, using care to ensure that each sample is taken atan adequate distance downstream from the proportionerbeing tested. (Usually any place downstream of the firstchange in direction is adequate if samples are taken in theriser room.) Stabilize a water flow through your dischargedevice within the known acceptable range for the propor-tioner and open the concentrate control valve. Take thesample about 30 to 60 seconds after foam appears fromthe test connection. Take meter readings of the sample(s)and compare readings to the plotted curve to determine thepercentage for each sample.

Per NFPA 11, Standard for Low-, Medium-, and High- Expansion Foam, acceptable ranges of proportioningsystems are not less than the rated concentration and notmore than 30% above the rated concentration or onepercentage point above the rated concentration, whicheveris less. For example, the acceptable range for a 3%concentrate is from 3 to 3.9%.

N)-": There is some variability dependent on the accuracyof the meter, the accuracy to which the calibration sampleswere made, and if temperatures between calibration stan-dards and discharge samples have not normalized.Conductivity is especially susceptible to reading fluctuation,thus the sample should be continuously stirred until a stabi-

lized reading can be estimated. Care should be taken tonot bump the sides or bottom of the sample container orcontaminate the sample with salts or solids, i.e. dirty fingerswhile stirring. The conductivity of water stored in or forsystems can vary throughout a discharge which may affectresults. Conductivity should not be used for sea, salt, orbrackish water supplies. Although conductivity can be themost accurate means of measuring foam solution in cleanwater supplies under ideal conditions, the refractive indexmethod is best for most real world testing.

If discharge samples are sent to the Tyco Fire ProtectionProducts Test Lab for analysis, they should be packagedper the instructions with the Test Kit and sent in for immedi-ate processing. Largely dependent on water quality and thetype of concentrate used, foam solutions may start tobiodegrade in a short period of time which can affect results(possibly as little as three to five days with nutrient-richwater and detergent-based foam concentrates).

The following graphs are examples of typical refractiveindex values for various concentrate pre-mixes. Resultsmay vary depending on the concentrate pre-mix type, sitewater supply, and actual concentrate lot number. Therefore,it is important that a new calibration curve be developed oneach date a proportioning test is required.



TypICal CalIbRaTION CURve ResUlTs WheN UsINg paRT NO. 405713 haNDhelD ReFRaCTOmeTeR

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NOTes:

NOTes

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CUSTOMER/LOCATION: ____________________________________________________________ FILE NO.: ____________

DATE: __________________________________________ TESTED BY: __________________________________________

FOAM CONCENTRATE TYPE / LOT NO.:______________________________________________________________________

METER TYPE:________ CONDUCTIVITY:________ REFRACTOMETER MODEL: __________________________________

P E R C E N T F O A M S

O L U T I O N

METER READING

CALIBRATION STANDARDS METER READING

FOAM CONCENTRATE

WATER

PRE-MIX #1 —

PRE-MIX #2 —

PRE-MIX #3 —

CalIbRaTION CURve

SYSTEM DISCHARGE SAMPLE METER READING PERCENT FOAM SOLUTION

FIelD INspeCTION ReCORD

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P a r t N o .

3 1 2 7 4 - 0 7

C o p y r i g h t © 2

0 1 1 T y c o F i r e P r o t e c t i o n 0 P r o d u c t s

A l l r i g h t s r e s e r v e d .

TYCO FIRE PROTECTION PRODUCTS

ONE STANTON STREET

MARINETTE, WI 54143-2542

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Prueba de Refractometro