THE SELECTION OF METERS
One of the ways that water departments are trying to meet and balance increased cost of labor and materials with available income is by close investigation of the necessities for purchase. In every branch of work, study is being made that will develop a proper solution of the problem of keeping service at a maximum with a minimum of expenditure. Many ways of doing this are apparent, such as conservation of the coal pile, fewer main pipe extensions, general installation of the meter system and similar matters. Among the things perhaps less obviously important is the purchase of meters to meet individual requirements. The right answer to the question, what size of meter to install on a given water service connection is one well worth consideraftion. On the one hand is the consumer, urged on by the plumber, clamoring for a large sized meter in order to get a large flow of water with little loss of pressure. On the other hand is the water department expenditure soaring higher and higher as the price of meters rises due to increased cost of production. In those cities where a service charge or a minimum rate is made dependent on the size of the service the expense of installation is not so important as where no such charge is made.
Per Capita Requirement Increasing.
Study of water department reports indicates that the per capita requirement for water is increasing in this country as a legitimate result of more extended use, especially in larger places. It appears that besides the increase in total consumption to be expected as the number of people supplied becomes larger there is also a gradually increasing individual use of water. The general introduction of meters will help very materially in reducing waste, and thus aid in conserving water. The fact must not be lost sight of, however, that each place has its own characteristic irreducible minimum below which it is impracticable to reduce consumption and above which there is a constant tendency for proper increase.
Causes of Condition.
This condition so far as it relates to domestic use may be due to several causes, among which are: First, plumbing installation in houses not previously having such conveniences: second, increase in the number of fixtures in houses already having plumbing fixtures; third, the installation of more modern plumbing devices which require water at high pressure and in comparatively large amounts for short periods. This last reason is of most interest in connection with the subject of this paper, because of its direct connection with the size of meter to be installed, the cost relative to the amount paid by the consumer, and the burden of the expense of installation and upkeep to the department. Advance in the plumbing art aims to control waste and to increase efficiency. The tendency in flushing is to produce a sudden deluge for a short period instead of the former lesser rate of discharge extending over a long period. For example, flushometer closets and urinals are very effective and usually economical in the total use of water. These fixtures, however, demand larger service pipes and meters than the older tank closet in order that the pressure and velocity of the flushing water may be as high as possible.
Size Dependent on Rate of Flow.
The size of meter to be installed on a service is more dependent on the rate of flow required and the drop in pressure due to this How in a given meter than on the actual quantity of water to be passed through it. To meet these conditions with a view to economy as well as efficiency it is desirable to consider among other things: 1. The installation of larger service pipes instead of larger meters. 2. Proper provision in the house piping system to meet the demands of modern plumbing instead of installing large meters. 3. The selection of meters properly designed for the particular use to which they are to be put. Item 3 relates to the selection of meters and the results of some investigations given below may be of interest if only as a suggestion of possibilities. So far as accuracy of registration and durability goes there seems little to influence choice between any of the meters now put on the market by the half dozen or more reputable manufacturers of water meters. So far, however, as los& of head is concerned, meters of different makes now on the market show considerable variation.
Rates of Water in Operation.
During the past two years that this investigation has been going on, the saving in new and old installations is estimated to have totaled over $1,000. The following tables give rates of water actually observed in the operation of various fixtures using water:
Rates of Use of Water by Various Plumbing Fixtures.
Very little information seems to be available in regard to rates of flow in service pipes and their duration, and no device was found on the market for getting an autographic record of the continuous use of water through service pipes and meters. Having had some experience with the Freiz Automatic Rainfall Register, the writer suggested to one of his assistants the possibility of adapting the recording mechanism of this machine to the required purpose. After some experimentation, J. E. Garratt, office engineer of the department’s staff, suitable electric connections: between the meter-counter and the chart of a rain gage recorder, and carried out in an able manner the field work of investigation.
From the record of the apparatus some very interesting facts have, been learned regarding use and waste of water, The apparatus is carried in a box 18 x 18 x 20 inches and including box weighs about 4 pounds. The registering apparatus con sists, of an eight-day clock with driving mechanism for rotating a cylinder about 4 inches in diameter around which is the chart wrapped in one fold. Avery in genious device carrying the recording pen is operated by electric contact at each tip of the bucket in the rain gage or each revo lution of a counter in the case of a meter. The drum makes an entire revolution every six hours and the pen describes a spirai on the rotating chart the lines of which are about 1/4 inch apart and thus avoid being superimposed. Rate of flow is indicated by the number of contacts registered by the pen on the chart, each contact denoting a revolution of the meter counter.
•Excer_____ from a paper read before the New England Water Works Association November 13, 1918.
The Use of the Recorder.
For an example of the use of the recorder, on the No. 576 Farmington avenue chart the record began about 10:40 a. m., Tuesday, June 12, and the preparations for lunch are clearly shown. At 11:47 a draft of about 2.5 cu. ft. per min., at 12 noon another draft of a similar amount. Throughout the afternoon there was some use up to about 3 p. m., then a period of comparative rest until about 6 p. m., when for two hours, during the dinner period, there was intermittent use. At about 10:25 a use of about 5 cu. ft. in four minutes indicates possibly the filling of a bathtub. From this time until 6:17 the next morning there was no flow, indicating either remarkably tight plumbing or a meter which failed to register small flows. From 7:10 to 8:50 a considerable use of water is noted, used probably for bathing and for the family breakfast. The maximum use in the house on this day was 1.25 cu. ft. per min. and it is noted that the recording mechanism checked the meter reading of 68 cu. ft. for the 24 hours use. The house under consideration is a one-family dwelling in the best residential part of Hartford, built perhaps 12 or 15 years ago. It is generally occupied by six persons and in the year 1916 had a total use of 16,400 cu. ft., equivalent to an average per capita consumption of 56 gals, per day. The water pressure here is about 70 pounds. The premises were originally served through a ⅝-inch meter. A complaint was made of inadequate service, and a new 1-inch service pipe was installed by the owner. A request for a 1-inch meter was made on advice of the plumber. A ¾-inch meter was attached and the owner was rather put out at first because the larger sized meter was not installed. The water fixtures in this house comprised: Three set tubs in laundry, one sink in laundry, and one sink in kitchen, all with hot and cold water; two water closets, tank type; four wash stands and one bath tub with hot and cold water; two ¾-inch hose bibs in garage and one ¾-inch sill cock. In investigating this house the following report was made: “With two cold water faucets open in the basement laundry and one hose connection in the garage, only a fair flow of water was obtained in the bathroom faucets on the second floor. With this demand the ⅝-inch meter showed a rate of 2.25 cu. ft. per minute, which is in excess of the ‘maximum proper rate of flow.’ A ¾-inch meter is recommended.” This installation has been perfectly satisfactory.
Higher Priced Meters Justifiable.
Six dollars per year is about the amount paid on many services supplying small families on which ⅝-inch meters are installed at a present cost of $15. There seems to be no logical reason why it is not as desirable to receive pay for water passing through the service whether it be a large or small consumer. If a more accurate measuring device than those in present use will necessitate paying a higher price than the present type of meter costs, water departments can well afford to pay the additional cost if they can be assured of more accurate results than seem possible with the present meter. The Brown School shows conditions as to use of water in a large public school building relative to the normal rates of use of water there. Maximum observed rate of use of at least 10 cu. ft. of water continuously as produced by normal use, 5.9 cu. ft. per min.; maximum observed rate of short duration and of small quantity (at recess time), 6 cu. ft. per min.; The fixtures supplied by this meter are as follows: Water closets (high tank flushed by seat), 23; urinals (automatically flushed from three tanks of same size as for closets), 12; wash stands, 13; drinking fountains. 6; faucets (equivalent to slop sink), 2; boiler for heating (low pressu_____e return feed), 1. The 2-inch meter originally on this building was capable of properly passing 20 cu. ft. of water per minute. The maximum observed rate under normal conditions of use was but 6 cu. ft. per min. This meter was replaced with a 1-inch meter at a saving of $42 on present prices. In addition to this, the accuracy of registration was increased by use of the smaller meter and the amount of unpaid for water reduced.
Record From a Laundry.
A chart from a laundry shows conditions where large quantities of water are used continuously during the day and thus indicates the type of meter which should be used under similar conditions. There is a 2-inch service about 50 feet long from the main to the meter. Inside about 75 feet of 2-inch pipe carried the water from the meter to the principal source of use. The following information was obtained relative to the usual rates of use of water: Maximum observed rate of use of at least 10 cu. ft. of water continuously as produced by normal use, 20 cu. ft. per min.; maximum observed rate of short duration, 5 cu. ft. in 15 secs., 20 cu. ft. per min.; rate produced when filling one large washing machine, 17 cu. ft. per min.; rate produced by opening two or more inlets to large washing machines, 20 cu. ft. per min. The limit of the system is apparently 20 cu. ft. per min. The fixtures supplied with water at this laundry are as follows: Washing machines—very large, 1; large, 5; small, 3; water closets, high tank, 3; low tank, 1; sinks, 2; set tubs, 7; faucets in barn (six horses stabled in barn), 2; boiler, 100 h. p. low pressure, return feed, 1. There arc 60 employees at this establishment. The 2-inch Trident Crest meter on this laundry is capable of properly passing 33 cu. ft. of water per minute. The maximum possible amount which the piping system is capable of delivering is apparently 20 cu. ft. per min. The meter is able to handle this quantity easily. A service for any similar installation with more adequate piping should be at least 3-inch.
These Conditions Typical.
The records of the use of water in the private house are representative of conditions in a large number of houses in Hartford and elsewhere. Probably the demand in these houses is much larger than in many others, yet even in these examples, it appears that the maximum rates observed arc only just within the limits of the 4 per cent accuracy which is the best the meter manufacturers are willing to guarantee. The bulk of the use of water in private houses of the class here noted is apparently at a rate of from 0.5 to 1 gallon per minute. The accuracy of registration for this rate on the basis of the meter manufacturer’s schedule for this size of meter is probably about 92 per cent, that is, on such services in ordinary use about 8 per cent of the water used is not accounted for. A ⅝-inch meter would account for a much greater proportion of the water drawn. On the other hand, its use would be totally unsatisfactory to the consumer because it would cut down the pressure when large quantities of water were required, and so interfere with the efficient operation of the plumbing.
The conditions shown above and the expressed opinions of specialists in water consumption matters indicate plainly that the time has come when more attention should be given to the design of meters with a view to greater accuracy on low flows and less friction on the high ones, even if the cost of the water is increased thereby. Also it appears that too much “tolerance” in meter design cannot be tolerated by water departments, especially by those where water is filtered or pumped and every unnecessary gallon sent to the distribution system means not only waste of water but increase in the annual cost for maintenance and operation. The compound meter was a long stride toward more accurate accountability on those services where there are intermittent calls for large quantities of water.