This page describes the various methods used to determine the water blaster measurements and statistics recorded for detailed soaker reviews. See the Conversions page for a listing of general measurement units and the formulae used at iSoaker.com to convert from one unit to another.
Water blaster, blaster add-ons, and device weights are measured using a Pelouze 2kg Commercial Parcel tabletop scale (Model K4). Due to the nature of the scale, measured weights are accurate to within +/- 5g. Items to be weighed must balance completely on the top of the scale's weighing platform.
The height, width, and length of a blaster is measuring using a 1.5m tape measure. Guides (often large textbooks) are placed at the widest, longest, or tallest portion of the blaster. The distance between the inner edges of the guides are measured. Using this method, blaster dimensions are measured with the approximate accuracy of +/- 0.5cm.
Three different volume measuring devices are used depending on the amount of water to be measured: 50 mL cup, 250 mL cup, and a 1L measuring cup. For volumes less than 50 mL, the accuracy of measuring is within +/- 1 mL. For larger volumes (generally above 500mL), accuracy drops to +/- 10 mL.
To determine reservoir volumes, reservoirs are filled completely with water, then have their caps attached (or be reattached to the soaker if applicable). The reservoir is then re-opened and water is emptied into the appropriate measuring cup. For reservoirs larger than 1 L, the measuring cup is filled to the 1 L mark, then emptied and filled again with the remaining water in the reservoir until no more water remains.
The volume reported for separate firing chambers is not the full phyiscal internal volume of a pressure chamber, rather the total volume of water that can be pushed out from a fully pressurized firing chamber. To determine firing chamber volumes, a blaster with a separate firing chamber is pumped until pumping becomes difficult and/or maximum pressure is reached on the pressure gauge or water is coming out from the check-valve. Once fully pressurized, the blaster is fired once to fill the space between the firing chamber and nozzle with water. The blaster is then repressurized, the nozzle is placed within a bottle and fired until no more water comes forth. The volume captured by the bottle is measured. This is repeated a few times to verify consistency of measurement. In all cases, before volumes are measured, blasters are properly primed to eliminate any air in tubings (or air in elastic-based pressure chambers). Once a water blaster is fired completely, there is typically some water that remains in internal tubing and even in the pressure chamber's dead space, but this water is not included in the pressure chamber volume measurement.
To determine pump volumes for blasters that pump water, the blaster is pumped multiple times while depressing the trigger until a consistent flow is produced with each pump. The nozzle is then placed into a bottle and the blaster is pumped five times while depressing the trigger. The volume collected in the bottle is measured and divided by five to yield the pump volume.
Guide-sticks are set up along a level firing range to mark off the start and at 10-foot intervals to a maximum distance of 60 feet (as of the time of this writing, no blaster has been able to fire farther than 60 feet). To determine the range of a blaster, the blaster is filled to its maximum capacity (Note: in the case of pressurized-reservoir-based blasters, their reservoirs are filled to 70% maximum capacity based on total reservoir volume). The blaster is then pumped until pumping become difficult and/or a check-valve begins letting water or a pressure gauge reads maximum. Then, the nozzle is held roughly directly over the start marker and the blaster is fired either horizontal to the ground or arced upwards at a 45-degree angle at a height of roughly 1 meter. Angle is determined by holding a leveler along side the blaster and aligning the appropriate read-out. Range is measured approximately by watching where along the guide marks the end-point of the stream reaches. When possible, a second person stands to the side to help determine the stream end-point. Range accuracy is estimated at +/- 12 inches.
Blaster output is actually a measure closer to a blaster's maximum output as opposed to its average output. To measure output, a blaster is filled with water (70% full if measuring a blaster that uses a pressurized reservoir), then pumped until pumping becomes difficult and/or water begins escaping through the check valve. The blaster is fired once simply to fill the area between the pressurized chamber and the nozzle with water, then the blaster is re-pumped to maximum pressure. After, the nozzle of the blaster is then placed into a bottle. The trigger is squeezed as a timer is started and released within one second, stopping the timer at the same time. The volume of water collected in the bottle is measured and the time recorded. The volume is then divided by the recorded time to yield the output measurement in volume per second. This is repeated a few times and an average is taken.
Output Rating is a relative term based on the highest output recorded for a stock soaker. Presently, the highest output recorded for a soaker is for the CPS2000 which is given an Output Rating of 100. All other soakers are scaled accordingly. Thus, a soaker with an Output Rating of 10 pushes out 10% of the output of the CPS2000.
The newest stat to be included in the blaster review is Power Rating. Basically, iSoaker.com is against using diameter or output alone to compare the true worth of a water blaster's stream. iSoaker.com currently rates nozzles based on actual water output (volume released per second) compared to the output of the standard issue XP70 (this is supposedly how Larami/Hasbro does their nozzle ratings). However, the true power of a soaker is not measured in output. The best way to truly compare soaker power is to multiply output by range and then compare those numbers. The following is the math behind why this is so...
* * * * PHYSICS ALERT!!! * * * *
Force = mass * acceleration
Work = Force * distance
Power = Work / time = (mass * acceleration * distance)/time
Also, Output = volume / time = ~ mass / time
Therefore: Output * distance = Power / acceleration
==> Power = Output * distance * acceleration
CRITICAL ASSUMPTION: If we assume that the rates at which water is accelerated in different soakers are more or less equal, dividing the number from the Output * Distance calculation of a soaker nozzle in question by the number from Output * Distance calculation for the standard XP70 will yield an appropriate ratio by which to compare soaker nozzle strengths.
Power rating of the most powerful soaker is set at 100. All other soakers are compared to the top soaker (which is currently the CPS2000) and are given as percentages. To compare any two nozzle power ratings, simply divide one by the other to see how much better (or worse) a nozzle setting is compared to the other.
Shot time provides a sense of how long a water blaster's stream lasts. At present, shot times are rounded to the nearest 0.5s mark. For water blasters whose power decreases as a shot progresses, shot time is defined as the time that the stream performs at least ~80% of its optimal performance.
Unlike the other numbers given in the reviews, iSoaker.com ratings are more subjective and based on general experience using a wide variety of stock soakers. Ratings are based on a 100 point system and are typically stepped at 10 points (though the odd 5 point rating difference may be spotted from time to time). iSoaker.com ratings are no longer adjusted for soaker size, though size does affect some of the ratings.
There are six ways iSoaker.com rates blasters: Power, Range, Encumberance, Ergonomics, Capacity, and Overall.
The Power rating provides a rough approximiation of the stream performance of the soaker. Power rating is currently scaled to 100 for blasters that have power levels equal or greater than the largest nozzle setting on a Super Soaker CPS 2500.
The Range rating provides a quick ranking of how far a water blaster's stream can reach with streams getting over 12m (~40') being given a rating of 100. The 12m milestone was chosen for range based on looking at the collective variety of measured ranges recorded in the iSoaker.com Database.
The Encumbrance rating provides a rough feel of how heavy or restrictive the soaker feels to move around with. While filled weight plays a major role when it comes to increased Encumbrance rating, the rating is also affected to some degree on how weight ends up distributed, particularly if some or most of a water blaster's weight is pushed onto one's shoulders versus needing to be carried solely by one's arms. Pistol-sized blasters tend to be given an encumbrance rating of 30 or less with large blasters (e.g. Super Soaker CPS 4100) usually being rated above 70.
The Ergonomics rating offers insight into how good a water blaster feels both to hold, carry, as well as to operate. Well designed, balanced blasters receive higher Ergonimics ratings than those that are imbalanced, awkward, or have other design problems that may make it more difficult for some users to use a particular blaster to its full potential.
The Capacity rating is a rough approximation of how much water a soaker can carry. There is a finite limit to the amount of water any given sized soaker can carry. More water yields higher numbers for this rating. Pistol-sized water blasters tend to hold ~500mL while large water blasters hold well over 1.5L.
The Overall rating takes the initial ratings as well as other things such as feel, style, durability, features, average cost, and reliability into account. However, by doing so, this makes this rating by far the most subjective. This rating is also based on personal preference on what is considered good traits for a soaker to have which can vary from individual to individual.
Additional Information .: