Overview
ISO 23590:2020 - Household biogas system requirements defines safety and performance requirements for small Household Biogas Systems (HBSs) with an annual biogas production capacity of less than 100 MWh and piping pressures below 5 kPa. The standard covers the full lifecycle of an HBS: design, installation, operation, maintenance and safety, and clarifies terms (biogas, digester, digestate, SRT/HRT) used for household-scale anaerobic digestion.
Key topics and technical requirements
- Scope and definitions: Applies to HBS units serving a single household (cooking, heating, lighting or small electrical power) and to components up to 5 kPa; appliances using the biogas are excluded.
- System components: Specifies required devices such as biomass inlet, digester, biogas storage and outlet, transfer system, digestate outlet, H2S filter, optional disinfection unit, excess gas release valve and a manual shutoff valve.
- Materials: Materials must be compatible with a biogas environment, meet minimum tensile strength and low gas-permeability limits, be non-hazardous and not contaminate biomass/digestate.
- Digester design:
- Install preferably outdoors or in well-ventilated spaces (≥5 air changes/hour).
- Internal/external surfaces must be free of hidden defects; piping and internal components must be securely anchored.
- Instrumentation (pressure/temperature monitors) and filters are allowed.
- Retention time: Solid retention time (SRT) shall not be less than 20 days. Digester volume calculation:
V = (S × SRT) × (1 + O/100)
where V = digester volume, S = daily substrate input, SRT = days, O = overhead volume (%).
- Pressure and leak testing: No leakage permitted during hydrostatic testing at 150% of regular working pressure; system must exclude air ingress.
- Safety features: Automatic excess gas release valve (operates >20% above working pressure), manual shutoff valve in parallel, allowed chimneys for excess gas, monitoring/alarm systems, and specific marking, warranty and documentation requirements.
- Operation & maintenance: Requirements for manuals, testing and sampling criteria, troubleshooting and maintenance procedures are included.
Applications and users
ISO 23590:2020 is intended for:
- HBS designers, manufacturers and suppliers
- Installers, system integrators and quality/control engineers
- NGOs, rural energy programs and development agencies deploying household biogas
- Regulators, inspectors and household owners seeking safe, compliant biogas installations
Use the standard to ensure safe digester sizing, material selection, pressure integrity, ventilation and routine maintenance practices for household biogas projects.
Related standards
- Prepared by ISO/TC 255 (Biogas). Many definitions reference ISO 20675 - consult normative references in ISO 23590:2020 for related biogas standards and terminology.