> For the complete documentation index, see [llms.txt](https://docs.datacake.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.datacake.de/dashboards/widgets/ashrae-chart-widget.md). # ASHRAE Chart Widget The ASHRAE Chart Widget helps visualise temperature or relative humidity measurements against the environmental classes defined in the ASHRAE Handbook for museums, galleries, archives, and libraries. It allows facility managers, conservators, and collection-care professionals to assess how closely environmental conditions align with a selected preservation class over time. ## Overview The widget compares a single metric, either temperature or relative humidity, against one of the ASHRAE museum climate classes and displays compliance percentages for each class. The supported classes are based on: **ASHRAE Handbook – HVAC Applications**\ Chapter: **Museums, Galleries, Archives, and Libraries** The widget is intended for: * Museums * Galleries * Archives * Libraries * Collection storage facilities {% hint style="info" %} **Important:** This widget is not based on ASHRAE TC 9.9 and should not be used to evaluate data-center environmental compliance. {% endhint %} ### Supported ASHRAE Classes | Class | Description | | ----- | ---------------------------------------------------------------- | | AA | Precision control with minimal fluctuation and no seasonal drift | | A | Precision control with limited seasonal drift | | As | Wider temperature drift with tighter humidity requirements | | B | Broad seasonal drift and relaxed control | | C | Fixed acceptable range | | D | Relative humidity maintained below 75% | *** ### What Can Be Visualised? Each widget instance displays a single metric: * Temperature * Relative Humidity To monitor both metrics, add two separate widget instances to your dashboard. ### Not Supported The widget does not calculate or display: * Dew Point * Wet Bulb Temperature * Psychrometric Relationships * Temperature/Humidity Correlation * ASHRAE TC 9.9 Recommended or Allowable Zones ## Configuration ### Data Select the device and field containing temperature data, or relative humidity data. Only one metric can be displayed per widget. ### Setpoint The setpoint represents the desired target value around which the ASHRAE class boundaries are calculated. Examples: * 20 °C for temperature * 50 % RH for humidity #### Seasonal Curve The widget supports three seasonal adjustment models: **Sine:** A smooth annual transition between summer and winter conditions. **Step:** Summer and winter conditions switch abruptly: * April–September: Summer * October–March: Winter **Step with transition:** Similar to Step, but includes approximately 30-day transition periods between seasons. #### **Drift AA Class with Season** When enabled, the AA class envelope follows the selected seasonal curve and shifts throughout the year. When disabled, the AA class remains centred around the configured setpoint and does not apply seasonal drift. {% hint style="info" %} This option only affects the AA class visualization and compliance calculation. Other classes continue to follow their respective ASHRAE definitions. {% endhint %} ### Classes Select the desired preservation class: * AA * A * As * B * C * D The selected class determines: * The visual compliance envelope * Compliance percentage calculations * Optional out-of-range indicators ### Understanding Compliance Percentages The percentages shown below the chart indicate how many samples fall within each ASHRAE class. For relative classes (AA, A, As, and B), Datacake evaluates compliance using the widest possible envelope of the class. This guarantees cumulative results: ``` AA ≤ A ≤ As ≤ B ``` For example: | Class | Compliance | | ----- | ---------- | | AA | 72% | | A | 85% | | As | 94% | | B | 99% | Since each class is progressively less restrictive, compliance percentages can only increase. ### Understanding Seasonal Drift For classes AA, A, As, and B, the acceptable range changes throughout the year. The center of the acceptable band is calculated using: ``` center(t) = setpoint + seasonalFactor(t) × seasonalAmplitude ``` The allowed range around that center is determined by the class-specific fluctuation limits. Classes C and D use fixed absolute limits and are not affected by seasonal drift. ### Indicator #### Out-of-Target Indicators Optional red outline markers can be displayed for samples that fall outside the selected target class. When enabled, the widget displays markers on all samples that fall outside the chosen target class at the corresponding timestamp. This can help quickly identify periods where environmental conditions exceeded the allowed limits. #### Target Class Select the ASHRAE class that should be used as the compliance reference for the out-of-class indicators. #### Compliance Enable **Show compliance percentages below chart** to display compliance statistics for each ASHRAE class. The percentages indicate how many measurements within the selected timeframe comply with each class. ### Intended Use Cases The ASHRAE Chart Widget is designed for: * Museum collection preservation * Archive climate monitoring * Library environmental control * Historic building conservation * Art storage facilities It provides a convenient way to assess long-term environmental stability and preservation compliance. ### Limitations The widget is not suitable for evaluating: * Data-center environmental compliance * ASHRAE TC 9.9 conformance * IT equipment inlet conditions * Cooling optimization strategies * Dew-point based assessments These use cases require psychrometric analysis and simultaneous evaluation of temperature and humidity. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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