As of March 1, 2011
FIELDCalc is a tool developed by Tanks-A-Lot to calculate septic tank, treatment plant, and treatment field, mound or at-grade sizing and configuration scenarios based on the information provided by the designer and based on selected requirements of the Alberta Private Sewage System Standard of Practice and Alberta Standata PST2009-002. All measurements provided are expressed in imperial units. Additional information about the calculation methods embedded in FIELDCalc can be found in the Technical Notes on Pages 10-11.
FIELDCalc is a calculator only and the resulting dataset is not a design. Calculations do not consider setbacks, treatment boundaries, other site-specific variables or system performance. The designer is responsible for all aspects of the site evaluation, system performance, and compliance with the Alberta Private Sewage System Standard of Practice or other local ordinances. Tanks-A-Lot assumes no liability in relation to use of FIELDCalc reports for any purpose.
Information About Yourself
When you sign up for FIELDCalc you provide us with your name, company name, company address, email, work phone, and PSDS ticket number. In some cases we may ask for additional information for security reasons or to provide specific services to you. Users may access or update the personal information stored on their account through the edit user account screen.
Protection of Personal Information
Tanks-A-Lot takes precautions — including administrative, technical, and physical measures — to safeguard your personal information against loss, theft, and misuse, as well as against unauthorized
access, disclosure, alteration, and destruction.
Site Activity Information
We keep track of some of the data supplied by FIELDCalc user reports. This information is used to make FIELDCalc better, and to improve customer support.
Disclosure to Third Parties
Tanks-A-Lot does not disclose your personally identifiable information to third parties.
We may disclose information pursuant to subpoenas, court orders, or other requests (including criminal and civil matters) if we have a good faith belief that the response is required by law. This may include respecting requests from jurisdictions outside Canada where we have a good faith belief that the response is required by law under the local laws in that jurisdiction, apply to users from that jurisdiction, and are consistent with generally accepted international standards. We may also share information when we have a good faith belief it is necessary to prevent fraud or other illegal activity, or to prevent imminent bodily harm. This may include sharing information with other companies, lawyers, courts or other government entities.
FIELDCalc is not a Computer Aided Design tool and should only be used by qualified designers
exercising professional discretion. Any dataset scenario selected for inclusion in a design
should be comprehensively reviewed by the designer for validity of performance and for
compliance with Alberta Private Sewage Systems Standard of Practice ("SOP"). 'At-Grade'
calculations are provided following Alberta Standard PST 2009-002. Approval of 'at-grades'
is a municipal matter and a variance application must be included with the permit application.
Tanks-A-Lot Ltd. is not liable for use of or reliance upon FIELDCalc results for any
FIELDCalc is a limited scope applied calculator following a linear sequential resolution
of certain prescriptive requirements in the SOP. The valid problem range that can
be considered within FIELDCalc is two to six bedroom homes or equivalent expected
volumes of residential strength sewage. Calculated solution ranges involve only
chamber based treatment fields, mounds or 'at-grades' with 1 ½" or 2" supply lines
and distribution laterals based on pressurized 1" or 1 ¼ " lines, irrespective of
the suitability of that solution range and without regard to exploring for optimal
solutions outside of that range.
Certain parameters are treated as fixed within the solution range of a given FIELDCalc
dataset. No guidance is given as to the extent that dataset results are valid upon
variation of those parameters at the request of the designer.
The default setting for the orifice size parameter (1/8") is based on minimizing
the calculated result for minimum flow rate, which in turn serves as a minimization
strategy for the total dynamic head of the effluent distribution system and consequentially
the requisite effluent pump size. Dataset calculations use only the maximum orifice
spacing prescribed in the SOP, consistent with this flow rate minimization strategy
and notwithstanding that closer orifice spacing may result in superior treatment.
Orifice spacing for orifices sizes other than 1/8" are not validated or limited
within FIELDCalc against SOP Table A.1.A and must be manually considered by the
designer prior to requisitioning a FIELDCalc dataset for alternate orifice sizes.
Calculations do not ever consider horizontal travel time such as described in s.
188.8.131.52. Consideration of these and other limitations described in s. 8.1 - 8.3
are the sole responsibility of the designer.
Pump selections are based upon using manufacturer supplied pump curves to minimize
pump size within an upper limit selection of augmented total dynamic head for the
minimum flow rate of the indicated field or mound configuration.
Total Dynamic Head calculations within FIELDCalc consider head loss in fittings
using an 'equivalent pipe' methodology and center-fed "H" style patterns of distribution
laterals and zone valves where indicated. Minimum field or mound lengths prescribed
in the SOP are rounded up, and lateral length is maximized to a limit of 65 feet,
to establish an even number of laterals of identical length using 4 foot long chambers.
Minimum dose volumes shown in FIELDCalc datasets consider 5X lateral pipe 'scouring'
SOP requirements for maximum dose size. Minimum mound dose calculations do adjust
for gravitational draining of supply line pipe based on relative elevation of tank
inlet and mound distribution header. Maximum mound dose is based on 20% of expected
daily sewage volume, as adjusted for number of zones.
Mound infiltration width is dependent on the slope of the land. For 0-1% slope,
the infiltration area includes the upslope berm, sand width and downslope berm;
for greater than 1% slopes the infiltration area includes the sand width and the
Standata PST 2009-002 calls for erosion control if berm slope is steeper than 3:1
or in the event it is an 'at-grade' mound located in a non-treed area. FIELDCalc
considers a 6" layer of topsoil for 'at-grades' steeper than 3:1.
The distribution of effluent onto the sand layer must cover a minimum of 80% of the
area determined by the designed effluent hydraulic loading rate.
If the width of chamber required to minimize mound length does not directly fit
in the chart (left), you’re bumped up to the next row for the “Maximized Run Width”
scenario. For the “Minimized Run Width” scenario the width is reduced one row and the
mound is lengthened to achieve the required sand or LFH area.