Recode supports the adoption of performance codes that judge buildings and their systems on how they work in the real world. Most codes are currently prescriptive, based on assumptions about appearance, theoretical calculations, and laboratory tests of building materials that do not often reflect actual structural performance. Performance codes are based on field verification of a technology’s efficacy and ensuring that all installed systems are designed for testability. Performance codes place environmental quality standards and field testing at the center of regulation but do not mean that every system’s performance is monitored and tested.
Performance Standards in Onsite Sanitation Codes:
Performance codes start with setting a baseline reference for a pollutant outside the context of any specific technological solution, defining what needs to happen so that pollutant is transformed into something acceptable for release into the environment, creating general guidelines for designing systems to make this happen, verifying that pollution is actually being treated in the real world, and releasing performance data to the public.
Pollution is defined as “daily loadings” that an average person will put on a sanitation system through their excrement and washwater, defining quantities of feces, urine, and other sanitation concerns that a typical household generates, as well as concentrations of pollutants such as nitrogen and phosphorus found in each concern.
Performance is defined by logarithmic reductions of diseases and percent reductions in the discharge of nitrogen, phosphorus, and other concentrated pollutants in comparison to the baseline pollution standard with no treatment.
All installed systems must be accessible for testing. For septic systems, this means accessible ports in the tank and testing wells in the leach field or sand filter. In the event of an environmental or health concern, all systems are ready for testing.
A certain number of every new design or system must be field tested at the manufacturer or installer’s expense in order to verify their function. All future versions of a system are “deemed to comply.”
Accessible System Data:
The testing and verification methodology is openly available, as is all testing data and average installed costs. This data assists homeowners in making choices and policymakers in decisions.
Performance codes in Sweden and Finland
The points above are summarized from the codes in Finland and Sweden, who take very similar approaches based in laws growing out of US regulations: Both countries passed legislation modeled after the USA’s Clean Water Act in the 1970’s, and created EPA departments modeled on the US EPA. We like the direction taken in Finland and Sweden because of its clarity and simplicity, leading to readable and short regulations.
The Finnish rules are the Government Decree on Treating Domestic Wastewater in Areas Outside Sewer Networks (542/2003) [english], and by the end of 2013 all of Finland is required to be in compliance. The Swedish rules are Swedish EPA NFS 2006:7 [Swedish with English summary]. The nitty-gritty of performance rules in Sweden are:
Assume no less than 5 year-long household residents and calculate the total nitrogen (N) and phosphorus (P) produced by their excrement. Technologies must meet:
Low-Risk zones: 90% Phosphorus reduction, 50% Nitrogen reduction
High-Risk zones: 90% Phosphorus and 70% Nitrogen reduction.
Verification of performance is delegated to municipalities. That process is described somewhat in this summary of the SPCR 178 reuse rules: Municipalities must maintain documentation of selective testing at least every 5 years, for every stage of the process (from properties to transport, additional treatment, and reuse). Municipalities contract to Avloppsguiden to assist homeowners in making system choices.
Performance codes in the US
The National Onsite Wastewater Recycling Association has created a model code process supported by the US EPA. NOWRA’s model code does not follow the same performance standards we prefer, but does provide excellent guidance on implementing Design Standards and a Verification regime.
Maryland has implemented a Verification system and testing standards independent of NOWRA but similar in its aims.